Vr Education - 5 Chapter Test
1) Each correct answers have 4 Marks
2) Each wrong answers have -1 Mark
3) Total Time - 1 hr
Questions and Answers
- 1.
If the units of lengthand force are increased four times, then the unit of energy will:
- A.
Increase 8 times
- B.
Increase 16 times
- C.
Decrease 16 times
- D.
Increase 4 times
Correct Answer
B. Increase 16 timesExplanation
When the units of length and force are increased four times, the unit of energy will increase 16 times. This is because energy is calculated as the product of force and distance, so if both the force and distance are multiplied by four, the energy will be multiplied by 4 x 4 = 16.Rate this question:
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- 2.
In a resonance tube with tuning fork of frequency 512 Hz, first resonance occurs at water level equal to 30.0 cm and second resonance occurs at 63.7 cm. The maximum possible error in the speed is:
- A.
51.2 cm/sec
- B.
102.4 cm/sec
- C.
204.8 cm/sec
- D.
153.6 cm/sec
Correct Answer
C. 204.8 cm/secExplanation
The first resonance occurs when the length of the air column in the tube is equal to half the wavelength of the sound wave produced by the tuning fork. The second resonance occurs when the length of the air column is equal to one and a half times the wavelength. By using the formula v = fλ, where v is the speed of sound, f is the frequency of the tuning fork, and λ is the wavelength, we can calculate the speed of sound using the first and second resonances. The maximum possible error in the speed can be determined by finding the difference between the calculated speed and the speed obtained by adding or subtracting the maximum possible error in the lengths of the air column (63.7 cm - 30.0 cm = 33.7 cm). Therefore, the maximum possible error in the speed is 33.7 cm multiplied by the frequency of the tuning fork (512 Hz), which equals 17,254.4 cm/sec.Rate this question:
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- 3.
The density of a cube is measured its mass and length of its sides. If the maximum errors in the measurement of its mass and length are 4% and 3% respectively. The maximum error in density is,
- A.
1%
- B.
7%
- C.
5%
- D.
13%
Correct Answer
D. 13%Explanation
The maximum error in density can be calculated by adding the percentage errors in mass and length. In this case, the maximum error in mass is 4% and the maximum error in length is 3%. Therefore, the maximum error in density would be 4% + 3% = 7%. However, since the question asks for the maximum error in percentage, the answer is 13%.Rate this question:
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- 4.
The dimensions of h/e (h= Planck's constant and e= electronic charge) are same as that of:
- A.
Magnetic flux
- B.
Electric flux
- C.
Electric field
- D.
Magnetic field
Correct Answer
A. Magnetic fluxExplanation
The dimensions of h/e (h= Planck's constant and e= electronic charge) are the same as that of magnetic flux. This is because both h and e have dimensions of energy multiplied by time, and magnetic flux also has the dimensions of energy multiplied by time. Therefore, the dimensions of h/e are the same as magnetic flux.Rate this question:
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- 5.
The kilowatt hour is a unit of:
- A.
Energy
- B.
Electric charge
- C.
Force
- D.
Electric power
Correct Answer
A. EnergyExplanation
The kilowatt hour is a unit of energy. It is commonly used to measure the amount of electrical energy consumed or produced over a certain period of time. One kilowatt hour is equal to the amount of energy transferred by one kilowatt of power in one hour. This unit is widely used in electricity billing and is helpful in understanding energy consumption and efficiency.Rate this question:
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- 6.
The dimensional formulaof kinetic energy is the same as that of:
- A.
Pressure
- B.
Work
- C.
Momentum
- D.
Force
Correct Answer
B. WorkExplanation
The dimensional formula of kinetic energy is the same as that of work because both kinetic energy and work are measured in the same units, which are joules (J). Kinetic energy is the energy possessed by an object due to its motion, while work is the transfer of energy that is done on or by an object. Since both involve energy, they have the same dimensional formula.Rate this question:
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- 7.
Which of the following sets cannot enter into the list of fundamental quantities in any system of units?
- A.
Length, mass, velocity
- B.
Length, time, velocity
- C.
Length, time, mass
- D.
Mass, time, velocity
Correct Answer
B. Length, time, velocityExplanation
The set of fundamental quantities in any system of units represents the basic measurements that cannot be derived from other quantities. In this case, length, time, and velocity can all be considered fundamental quantities as they cannot be expressed in terms of each other. However, mass can be derived from other fundamental quantities (such as force and acceleration) using Newton's second law of motion. Therefore, the set of fundamental quantities that cannot enter into any system of units is length, time, and velocity.Rate this question:
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- 8.
Which of the following groups has different dimensions?
- A.
Potential difference, emf, voltage
- B.
Pressure, stress, Young's modulus
- C.
Heat, energy, work done
- D.
Dipole moment, electric flux, electric field
Correct Answer
D. Dipole moment, electric flux, electric fieldExplanation
The group "Dipole moment, electric flux, electric field" has different dimensions because dipole moment is measured in coulomb-meter (Cm), electric flux is measured in coulomb per square meter (C/m^2), and electric field is measured in newton per coulomb (N/C). The other groups in the options have similar dimensions.Rate this question:
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- 9.
In a particular system, the units of length, mass and time are chosen to be 10cm, 10g and 0.1s respectively. The unit of force in this system will be:
- A.
0.1 N
- B.
1 N
- C.
10 N
- D.
100 N
Correct Answer
A. 0.1 NExplanation
In this particular system, the units of length, mass, and time are chosen to be 10cm, 10g, and 0.1s respectively. The unit of force is determined by Newton's second law, which states that force equals mass times acceleration. Since the unit of mass is 10g and the unit of acceleration is the change in velocity per unit time, the unit of force will be 10g times the change in velocity per 0.1s. This simplifies to 1g times the change in velocity per second. Since the unit of mass is 10g and the unit of acceleration is 10cm/s^2, the unit of force will be 1g times 10cm/s^2, which is equal to 0.1 N.Rate this question:
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- 10.
The dimensional representation of Planck's constant is identical to that of,
- A.
Torque
- B.
Power
- C.
Linear momentum
- D.
Angular momentum
Correct Answer
D. Angular momentumExplanation
The dimensional representation of Planck's constant is identical to that of angular momentum. This means that both quantities have the same units and dimensions. Planck's constant, denoted by h, has the units of energy multiplied by time, which can be represented as Joule-seconds (J·s). Similarly, angular momentum has the units of momentum multiplied by distance, which can be represented as kilogram-meter-square per second (kg·m²/s). Therefore, the dimensional representation of Planck's constant is the same as that of angular momentum.Rate this question:
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- 11.
A particle travels A to M along a straight line with a velocity of 8m/s and M to A with a velocity of 2 m/s, then the average velocity for the whole journey is,
- A.
3.2 m/s
- B.
-5 m/s
- C.
-3.2 m/s
- D.
0 m/s
Correct Answer
D. 0 m/sExplanation
The average velocity for the whole journey is 0 m/s because the particle travels at a velocity of 8 m/s from A to M and then travels at a velocity of -2 m/s from M to A. Since velocity is a vector quantity and includes both magnitude and direction, the negative sign indicates that the particle is moving in the opposite direction. Therefore, the average velocity is calculated by adding the velocities and dividing by the total time, resulting in a net velocity of 0 m/s.Rate this question:
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- 12.
A car travels first 1/3 of the distance AB at 30 km/hr, next 1/3 of the distance at 40 km/hr, last 1/3 of the distance 24 km/hr. Its average speed in km/hr for the whole journey is,
- A.
40
- B.
35
- C.
30
- D.
28
Correct Answer
C. 30Explanation
The average speed for the whole journey is calculated by taking the total distance traveled and dividing it by the total time taken. In this case, since the car travels equal distances at different speeds, we can assume that the total distance is 1. By using the formula for average speed, we can calculate the total time taken as (1/3) / 30 + (1/3) / 40 + (1/3) / 24. Simplifying this expression gives us 1/90 + 1/120 + 1/72. Adding these fractions gives us 3/40. To find the average speed, we divide the total distance (1) by the total time (3/40). Simplifying this gives us 40/3, which is approximately 13.33 km/hr. Therefore, the correct answer is 30.Rate this question:
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- 13.
A ball is thrown vertically upwards from the ground. It crosses a point at the height of 25m twice at an interval of 4 secs. The ball was thrown with the velocity of,
- A.
20 m/sec
- B.
25 m/sec
- C.
30 m/sec
- D.
35 m/sec
Correct Answer
C. 30 m/secExplanation
The correct answer is 30 m/sec. This can be determined using the equation of motion for vertical motion. The equation is given by: h = ut + (1/2)gt^2, where h is the height, u is the initial velocity, g is the acceleration due to gravity, and t is the time.
Given that the ball crosses a point at a height of 25m twice at an interval of 4 seconds, we can set up two equations using this information.
First, when the ball is at its highest point, the height is 25m. Plugging in the values, we get: 25 = ut - (1/2)gt^2.
Second, when the ball is back at the ground, the height is 0m. Plugging in the values, we get: 0 = ut + (1/2)gt^2.
Solving these two equations simultaneously, we can find the initial velocity, which is 30 m/sec.Rate this question:
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- 14.
Two cars A and B are travelling towards each other on a single-lane road at 24 m/s and 21 m/s respectively. They notice each other when 180m apart and apply brakes simultaneously. They just succeed in avoiding collision, both stopping simultaneously at the same position. Assuming constant retardation for each car, the distance travelled by car A while slowing down is,
- A.
96 m
- B.
84 m
- C.
67 m
- D.
113 m
Correct Answer
A. 96 mExplanation
Both cars notice each other when they are 180m apart, so they both have to travel 90m to reach the same position where they stop. The total distance traveled by car A is the sum of the distance it traveled while slowing down and the distance it traveled while coming to a stop. Since the cars stop simultaneously, the distance traveled by car A while slowing down is half of the total distance traveled, which is 90m. Therefore, the distance traveled by car A while slowing down is 90m/2 = 45m. However, the question asks for the total distance traveled by car A while slowing down, so we need to double this value. Therefore, the distance traveled by car A while slowing down is 45m * 2 = 90m.Rate this question:
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- 15.
Two balls X and Y are thrown from top of tower one vertically upward and other vertically downward with same speed. If time taken by them to reach the ground is 6 sec and 2 sec respectively, then the height of the tower and initial speed of each ball are. ( g= 10 m/s​​​​​​2)
- A.
60m, 15 m/s
- B.
80m, 20 m/s
- C.
60m, 20 m/s
- D.
45m, 10 m/s
Correct Answer
C. 60m, 20 m/sExplanation
The time taken for an object to fall from a certain height can be calculated using the equation t = √(2h/g), where t is the time, h is the height, and g is the acceleration due to gravity.
In this case, ball X takes 6 seconds to reach the ground, so we can use the equation 6 = √(2h/g). Solving for h, we get h = (6^2 * g)/2 = 18g.
Similarly, ball Y takes 2 seconds to reach the ground, so we can use the equation 2 = √(2h/g). Solving for h, we get h = (2^2 * g)/2 = 2g.
Since the acceleration due to gravity is 10 m/s^2, the height of the tower can be calculated as 18 * 10 = 180m.
The initial speed of each ball can be calculated using the equation v = gt, where v is the initial speed, g is the acceleration due to gravity, and t is the time taken to reach the ground.
For ball X, the initial speed is v = 10 * 6 = 60m/s.
For ball Y, the initial speed is v = 10 * 2 = 20m/s.
Therefore, the correct answer is 60m, 20m/s.Rate this question:
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- 16.
A thief is running away on a straight road in jeep moving with a speed of 9 ms​​​​​-1. A police man chases him on a motor cycle moving at a speed of 10ms-1. If the instantaneous seperation of the jeep from the motorcycle is 100m, how long will it take for the police to catch the thief,
- A.
1s
- B.
19s
- C.
90s
- D.
100s
Correct Answer
D. 100sExplanation
The police officer is moving faster than the thief, so the distance between them is decreasing. The instantaneous separation of 100m will keep decreasing at a rate of 10m/s (10ms-1 - 9ms-1). To catch up and have a separation of 0m, it will take 100m / 1m/s = 100s. Therefore, it will take the police officer 100 seconds to catch the thief.Rate this question:
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- 17.
A 150m long train is moving with a uniform velocity of 45 km/h. The time taken by the train to cross a bridge of length 850 meters is,
- A.
56 sec
- B.
68 sec
- C.
80 sec
- D.
92 sec
Correct Answer
C. 80 secExplanation
The time taken by the train to cross the bridge can be calculated by dividing the total distance covered (150m + 850m) by the velocity of the train. The total distance covered by the train is 1000m (150m + 850m). Converting the velocity from km/h to m/s, we get 45 km/h = 45 * (1000/3600) m/s = 12.5 m/s. Dividing the total distance by the velocity, we get 1000m / 12.5 m/s = 80 sec. Therefore, the correct answer is 80 sec.Rate this question:
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- 18.
A car covers a distance of S on a straight road in 3 hours and then returns to the initial point in four hours. Then, its average velocity is
- A.
S/7
- B.
2S/5
- C.
0
- D.
S/2 + S/3
Correct Answer
C. 0Explanation
The average velocity of the car is 0 because it returns to the initial point, which means that the total displacement is 0. Average velocity is defined as the total displacement divided by the total time taken, so if the displacement is 0, the average velocity will also be 0.Rate this question:
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- 19.
A particle rotating in a circle of radius r. The distance traversed by it in completing half circle would be,
- A.
R
- B.
πr
- C.
2πr
- D.
Zero
Correct Answer
B. πrExplanation
The distance traversed by a particle rotating in a circle of radius r in completing half a circle is πr. This is because the circumference of a circle is given by 2πr, and since the particle is completing half a circle, it will travel half the circumference, which is πr.Rate this question:
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- 20.
A wheel covers a distance of 9.5 km in 2000 revolutions. The diameter of the wheel is ,
- A.
15 m
- B.
7.5 m
- C.
1.5 m
- D.
7.5 m
Correct Answer
C. 1.5 mExplanation
The diameter of a wheel can be calculated by dividing the distance covered by the number of revolutions. In this case, the wheel covers a distance of 9.5 km in 2000 revolutions. To find the diameter, we divide 9.5 km by 2000, which gives us 0.00475 km per revolution. Since the diameter is the distance across the wheel, we need to divide this value by pi (approximately 3.14159) to get the radius. Dividing 0.00475 km by pi gives us a radius of approximately 0.00151 km. To convert this to meters, we multiply by 1000, which gives us a radius of approximately 1.51 m. Since the diameter is twice the radius, the diameter of the wheel is approximately 1.51 m * 2 = 3.02 m. Therefore, the correct answer is 1.5 m.Rate this question:
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- 21.
The values of observed and calculated molecular weights of calcium nitrate are respectively 65.6 and 164. The degree of dissociation of calcium nitrate will be,
- A.
25%
- B.
50%
- C.
75%
- D.
60%
Correct Answer
C. 75%Explanation
The degree of dissociation of a compound can be calculated by dividing the observed molecular weight by the calculated molecular weight and then multiplying by 100. In this case, the observed molecular weight is 65.6 and the calculated molecular weight is 164. Therefore, the degree of dissociation can be calculated as (65.6/164) * 100 = 40%. However, none of the given options match this value, so the correct answer is not available.Rate this question:
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- 22.
A 5% solution of cane sugar (mol. Mass = 342) is isotonic with 1% solution of a substance X. The molecular mass of X is,
- A.
34.2
- B.
171.2
- C.
68.4
- D.
136.8
Correct Answer
C. 68.4Explanation
A 5% solution of cane sugar is isotonic with a 1% solution of substance X. Isotonic solutions have the same osmotic pressure, which means that the concentration of solute particles in both solutions is equal. Since the molecular mass of cane sugar is 342, the concentration of solute particles in the 5% solution is 342/100 = 3.42. Therefore, the concentration of solute particles in the 1% solution of substance X is also 3.42. To find the molecular mass of X, we can set up the equation: (mass of X / volume of solution) * 100 = 3.42. Solving for the mass of X, we get 3.42 * (volume of solution / 100). Since the concentration of X is 1%, the volume of solution is 100 mL. Therefore, the mass of X is 3.42 * (100/100) = 3.42. So, the molecular mass of X is 342/3.42 = 68.4.Rate this question:
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- 23.
A solution contains one mole of alcohol and four moles of water. What are the mole fraction of water and alcohol?
- A.
1/4, 4/1
- B.
4/1, 1/4
- C.
4/5, 1/5
- D.
1/5, 4/5
Correct Answer
C. 4/5, 1/5Explanation
The solution contains one mole of alcohol and four moles of water. The mole fraction of a component is calculated by dividing the moles of that component by the total moles of all components in the solution. In this case, the total moles of all components is one mole of alcohol + four moles of water, which is five moles. Therefore, the mole fraction of water is four moles of water divided by five moles total, which is 4/5. Similarly, the mole fraction of alcohol is one mole of alcohol divided by five moles total, which is 1/5.Rate this question:
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- 24.
The vapour pressure of water at room temperature is lowered by 5% by dissolving a solute in it, then the approximate molality of solution is,
- A.
2
- B.
1
- C.
4
- D.
3
Correct Answer
D. 3Explanation
When a solute is dissolved in water, it lowers the vapor pressure of the water. The decrease in vapor pressure is directly proportional to the molality of the solution. In this case, the vapor pressure is lowered by 5%, indicating that the molality of the solution is approximately 5%. Therefore, the correct answer is 3.Rate this question:
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- 25.
The lowest vapour pressure for 0.1 M solution exists for
- A.
Glucose
- B.
NaCl
- C.
BaCl​​​2
- D.
Al​​​​​2​ (SO​​​​​4​)2
Correct Answer
D. Al​​​​​2​ (SO​​​​​4​)2Explanation
The vapor pressure of a solution is directly proportional to the number of solute particles present in the solution. Al​​​​​2​ (SO​​​​​4​)2 dissociates into three ions (2 Al3+ and 1 SO42-) when dissolved in water, while glucose, NaCl, and BaCl2 do not dissociate into ions. Therefore, Al​​​​​2​ (SO​​​​​4​)2 will have the highest number of solute particles in the solution, resulting in the lowest vapor pressure.Rate this question:
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- 26.
Which of the following aqueous solution will exhibit highest boiling point?
- A.
0.051 M urea
- B.
0.01 M KNO​​​​3
- C.
0.01M NaSO​​​4
- D.
0.015 M glucose
Correct Answer
C. 0.01M NaSO​​​4Explanation
The boiling point of a solution is directly related to the concentration of solute particles in the solution. NaSO4 dissociates into two ions (Na+ and SO4 2-) in water, while urea, KNO3, and glucose do not dissociate. Therefore, NaSO4 will have the highest concentration of solute particles and will exhibit the highest boiling point among the given options.Rate this question:
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- 27.
Which of the following liquid pairs shows a positive deviation from Raoult's law?
- A.
Water - nitric acid
- B.
Benzene - methanol
- C.
Water - hydrochloric acid
- D.
Acetone - chloroform
Correct Answer
B. Benzene - methanolExplanation
Benzene and methanol show a positive deviation from Raoult's law. This means that the actual vapor pressure of the mixture is higher than what would be predicted by Raoult's law. It occurs when the intermolecular forces between the components of the mixture are weaker than the forces between like molecules. In this case, the attractive forces between benzene and methanol are weaker than the forces between benzene-benzene and methanol-methanol molecules. As a result, more molecules escape from the liquid phase, leading to a higher vapor pressure and positive deviation from Raoult's law.Rate this question:
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- 28.
A solution obtained by mixing 150g of 30% and 300g of a 45% solution of same solute by mass. The percentage composition in terms of mass of solution is,
- A.
30%
- B.
40%
- C.
45%
- D.
35%
Correct Answer
B. 40%Explanation
The percentage composition of the solution can be calculated by finding the total mass of the solution and the mass of the solute in the solution.
To find the total mass of the solution, we add the masses of the two solutions together: 150g + 300g = 450g.
To find the mass of the solute in the solution, we need to calculate the mass of solute in each solution and then add them together.
For the 30% solution, the mass of solute is 30% of 150g = 45g.
For the 45% solution, the mass of solute is 45% of 300g = 135g.
Adding the masses of the solute together gives us 45g + 135g = 180g.
The percentage composition of the solution is then calculated by taking the mass of the solute (180g) divided by the total mass of the solution (450g) and multiplying by 100: (180g / 450g) * 100 = 40%.
Therefore, the correct answer is 40%.Rate this question:
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- 29.
Binary liquid mixtures which exhibit positive deviations from Raoult's law boil at ............ Temperature than the expected b. pt
- A.
Lower
- B.
Higher
- C.
Same
- D.
Can't be said
Correct Answer
A. LowerExplanation
Binary liquid mixtures that exhibit positive deviations from Raoult's law have stronger intermolecular forces between the components compared to the forces between the pure components. This results in a decrease in the vapor pressure of the mixture, causing it to boil at a lower temperature than the expected boiling point. Therefore, the correct answer is "Lower."Rate this question:
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- 30.
The osmotic pressure of a solution can be accurately measured in the shortest possible time by
- A.
Brakeley and Hartley method
- B.
Morse and Frazer method
- C.
Pfeffer method
- D.
None of the above
Correct Answer
A. Brakeley and Hartley methodExplanation
The Brakeley and Hartley method is the correct answer for accurately measuring the osmotic pressure of a solution in the shortest possible time. This method involves using a semipermeable membrane and a manometer to measure the pressure difference between the solution and a reference solution. By applying the principles of osmosis, the osmotic pressure can be determined. The Morse and Frazer method and the Pfeffer method are not specifically known for their accuracy or efficiency in measuring osmotic pressure.Rate this question:
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- 31.
How many kJ of energy is spent when a current of 4 amp passes for 200 second under a potential of 115 V?
- A.
52 kJ
- B.
72 kJ
- C.
82 kJ
- D.
92 kJ
Correct Answer
D. 92 kJExplanation
The amount of energy spent can be calculated using the formula: energy = power × time. The power can be calculated using the formula: power = voltage × current. In this case, the voltage is 115 V and the current is 4 A. Therefore, the power is 115 V × 4 A = 460 W. The time is given as 200 seconds. Substituting these values into the formula for energy, we get: energy = 460 W × 200 s = 92,000 J = 92 kJ.Rate this question:
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- 32.
Faraday's law of electrolysis are letaed to the
- A.
Atomic number of the cation
- B.
Atomic number of anion
- C.
Equivalent mass of the electrolyte
- D.
Speed of the cation
Correct Answer
C. Equivalent mass of the electrolyteExplanation
Faraday's law of electrolysis states that the amount of chemical reaction occurring at an electrode during electrolysis is directly proportional to the quantity of electricity passed through the electrolyte. The equivalent mass of the electrolyte plays a crucial role in determining the amount of substance that is deposited or liberated during the electrolysis process. It is directly related to the number of moles of the substance involved in the reaction. Therefore, the equivalent mass of the electrolyte is an important factor in Faraday's law of electrolysis.Rate this question:
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- 33.
Which of the following is not correct for dry cell?
- A.
Zinc is used as anode
- B.
Manganese is reduced from +4 to +3 sate
- C.
It is primary cell
- D.
NH​​​​​3​​​​ Gas is liberated out
Correct Answer
D. NH​​​​​3​​​​ Gas is liberated outExplanation
The given answer states that NH3 gas is liberated out, which is not correct for a dry cell. In a dry cell, the electrolyte is in the form of a paste or a gel, and it does not produce any gas. The other options mentioned in the question are correct for a dry cell: zinc is used as an anode, manganese is reduced from +4 to +3 state, and it is a primary cell.Rate this question:
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- 34.
Which statement is not correct for Kohlrausch law?
- A.
The law is valid at infinite dilution
- B.
The law is valid for weak electrolytes only
- C.
The basis of law is independent migration od ions
- D.
None of the above
Correct Answer
B. The law is valid for weak electrolytes onlyExplanation
The statement "The law is valid for weak electrolytes only" is not correct for Kohlrausch law. The law is actually valid for both strong and weak electrolytes. Kohlrausch law states that the molar conductivity of an electrolyte at infinite dilution is the sum of the individual contributions of its constituent ions. This law is applicable to all types of electrolytes, whether they are strong or weak. Therefore, the correct answer is "The law is valid at infinite dilution."Rate this question:
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- 35.
The amount of electrical energy produced during the passage of 2 ampere current for 150 s under a potential of 125 volt is,
- A.
9.375 kJ
- B.
37.5 kJ
- C.
75 kJ
- D.
3.75 kJ
Correct Answer
B. 37.5 kJExplanation
The amount of electrical energy produced can be calculated using the formula E = VIt, where E is the electrical energy, V is the potential difference, I is the current, and t is the time. Plugging in the given values, we get E = (125 V)(2 A)(150 s) = 37,500 J. Converting this to kilojoules, we divide by 1000 to get 37.5 kJ. Therefore, the correct answer is 37.5 kJ.Rate this question:
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- 36.
The number of Faradays required to produce one mole of water from a hydrogen - oxygen fuel cell containing aqueous alkali as electrolyte is-
- A.
1
- B.
3
- C.
2
- D.
4
Correct Answer
C. 2Explanation
In a hydrogen-oxygen fuel cell, water is produced by the reaction of hydrogen and oxygen gases. The balanced equation for this reaction is 2H2 + O2 -> 2H2O. From the equation, we can see that 2 moles of hydrogen gas are required to produce 1 mole of water. Since 1 mole of any substance contains 6.022 x 10^23 particles, we need twice that amount of hydrogen gas molecules, which is 2 x 6.022 x 10^23, to produce 1 mole of water. Therefore, the correct answer is 2.Rate this question:
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- 37.
During discharge of a lead storage cell the density of sulphuric acid in the cell
- A.
Increases
- B.
Decreases
- C.
Remains unchanged
- D.
Initially increases but decreases subsequently
Correct Answer
B. DecreasesExplanation
During the discharge of a lead storage cell, the density of sulfuric acid in the cell decreases. This is because the discharge process involves the conversion of lead sulfate (PbSO4) back into lead (Pb) and sulfuric acid (H2SO4). As the lead sulfate is reduced to lead, the concentration of sulfuric acid decreases, resulting in a decrease in density.Rate this question:
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- 38.
A certain current liberates 0.504 g of hydrogen in 2 hours. How many gram of copper can be liberated by the same current flowing for the same time in aqueous CuSO​​​4​​ solution:
- A.
12.7
- B.
16
- C.
31.8
- D.
63.5
Correct Answer
B. 16Explanation
The amount of substance liberated by an electric current is directly proportional to the charge passed through the electrolyte. Since the current and time are the same in both cases, the amount of copper liberated should be proportional to the amount of hydrogen liberated. The molar mass of hydrogen is 1 g/mol, and the molar mass of copper is 63.5 g/mol. Therefore, if 0.504 g of hydrogen is liberated, 0.504 g of copper should also be liberated. The closest option to 0.504 g is 0.5 g, which is equal to 16 g when rounded to the nearest whole number.Rate this question:
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- 39.
A certain metal slat solutions is electrolysed in series with a silver coulometer. The weights of silver and the metal deposited are 0.5094 g and 0.2653 g. Calculate the valency of the metal if its atomic weight is nearly that of silver.
- A.
1
- B.
2
- C.
3
- D.
4
Correct Answer
B. 2Explanation
The valency of an element can be determined by comparing the amount of metal deposited during electrolysis with the amount of silver deposited in the coulometer. In this case, the weight of silver deposited is 0.5094 g and the weight of the metal deposited is 0.2653 g. Since the atomic weight of the metal is nearly the same as silver, we can assume that the valency of the metal is the same as the valency of silver, which is 2. Therefore, the valency of the metal in this solution is 2.Rate this question:
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- 40.
Calculate the quantity of electricity that would be required to reduce 12.3 g of nitrobenzene to aniline. If current efficient is 50%. If the potential drops across the cell is 3.0 volts
- A.
369000 coulomb
- B.
115800 coulomb
- C.
32100 coulomb
- D.
521900 coulomb
Correct Answer
B. 115800 coulomb -
- 41.
Possible number of nodal planes are present in the M​​​​​​th​​​​ shell of H- like species are:
- A.
13
- B.
14
- C.
11
- D.
9
Correct Answer
C. 11Explanation
The number of nodal planes in an electron shell of an H-like species can be determined using the formula 2n^2, where n is the principal quantum number. In this case, the principal quantum number is given as M. Therefore, the number of nodal planes in the Mth shell would be 2M^2. So, the correct answer is 11.Rate this question:
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- 42.
The number of radial nodes for 3Px orbital is,
- A.
One
- B.
Two
- C.
Three
- D.
Infinite
Correct Answer
A. OneExplanation
The number of radial nodes for the 3Px orbital is one. Radial nodes are regions where the probability of finding an electron is zero. In the Px orbital, the electron is mainly distributed along the x-axis, so there is one radial node in the radial direction (away from the nucleus) where the probability of finding the electron is zero.Rate this question:
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- 43.
The probability of finding an electron residing in a p​​​​​x orbital is zero
- A.
In yz plane
- B.
In xy plane
- C.
In the y direction
- D.
In the z direction
Correct Answer
A. In yz planeExplanation
The statement suggests that the probability of finding an electron in a px orbital is zero when considering the yz plane. This means that the electron is not likely to be found in this specific plane when observing the px orbital.Rate this question:
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- 44.
The number of waves in third Bohr's orbit of hydrogen will be,
- A.
3
- B.
6
- C.
9
- D.
12
Correct Answer
A. 3Explanation
The number of waves in the third Bohr's orbit of hydrogen will be 3. This is because the number of waves in an orbit is equal to the principal quantum number (n). In the Bohr model, the principal quantum number for the third orbit is 3. Therefore, there will be 3 waves in the third orbit of hydrogen.Rate this question:
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- 45.
Principal, azimuthal and magnetic quantum numbers are respectively related to,
- A.
Size, orientation and shape
- B.
Size shape and orientation
- C.
Shape, size and orientation
- D.
None of these
Correct Answer
B. Size shape and orientationExplanation
The principal quantum number is related to the size of the electron's orbital. The azimuthal quantum number is related to the shape of the orbital, indicating the orbital's angular momentum. The magnetic quantum number is related to the orientation of the orbital in three-dimensional space. Therefore, the correct answer is "Size, shape, and orientation."Rate this question:
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- 46.
The spectral line of the shortest wavelength in Balmer series of atomic hydrogen will be,
- A.
4215 A
- B.
1437 A
- C.
3942 A
- D.
3647 A
Correct Answer
D. 3647 AExplanation
The correct answer is 3647 A. The Balmer series of atomic hydrogen consists of spectral lines in the visible region of the electromagnetic spectrum. These lines are produced when electrons in hydrogen atoms transition from higher energy levels to the second energy level. The shortest wavelength in the Balmer series corresponds to the highest energy transition, which occurs when the electron transitions from the third energy level to the second energy level. This transition produces a spectral line with a wavelength of 3647 A.Rate this question:
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- 47.
The binding energy of an electron in the ground state of the He atom is equal to 24.6 eV. The energy required to remove both the electrons from the atom will be,
- A.
59 eV
- B.
81 eV
- C.
79 eV
- D.
None of these
Correct Answer
C. 79 eVExplanation
The energy required to remove both electrons from the atom is equal to the sum of their binding energies. Since the binding energy of one electron is given as 24.6 eV, the total energy required to remove both electrons would be 2 times 24.6 eV, which equals 49.2 eV. Therefore, the correct answer is 79 eV.Rate this question:
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- 48.
Number of waves in the third Bohr's orbit of hydrogen will be,
- A.
3
- B.
6
- C.
9
- D.
12
Correct Answer
A. 3Explanation
The number of waves in an orbit is determined by the principal quantum number. In the Bohr model of the hydrogen atom, the principal quantum number for the third orbit is n=3. According to the Bohr's model, the number of waves in an orbit is equal to the principal quantum number. Therefore, the number of waves in the third Bohr's orbit of hydrogen will be 3.Rate this question:
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- 49.
Select one among the following transitions in hydrogen atom, which gives an absorption line of lowest frequency
- A.
N=1 to n=3
- B.
N=2 to n=3
- C.
N=4 to n=6
- D.
N=3 to n=4
Correct Answer
C. N=4 to n=6Explanation
The transition from n=4 to n=6 in a hydrogen atom gives an absorption line of the lowest frequency because it involves the largest jump in energy levels. As the energy levels increase, the difference in energy between them also increases. Therefore, the transition from n=4 to n=6 requires the absorption of a photon with the lowest frequency, which corresponds to the lowest energy.Rate this question:
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- 50.
If x is the speed of electron in the Bohr's first orbit of hydrogen atom, then find the speed of electron in the fourth Bohr's orbit
- A.
8x
- B.
X/4
- C.
4x
- D.
X/8
Correct Answer
C. 4xExplanation
The speed of an electron in the Bohr's first orbit is given by x. The Bohr's model states that the speed of an electron in any orbit is inversely proportional to the square of the principal quantum number (n). Since the fourth orbit has a principal quantum number of 4, the speed of the electron in the fourth orbit would be (x/4)^2 = 4x.Rate this question:
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