1.
State and prove Gauss's Law in electrostatics and express the law in differential forms.(Give brief answers)
2.
Which techniques you will use to motivate the students?
3.
What would you do if the whole class is not getting the concept?
4.
How can you make learning fun for the students?
5.
Why should we consider you for the teaching job in our school?
6.
Waves travels on water surface through _____________________
Correct Answer
A. Molecules
Explanation
Waves travel on the water surface through the interaction and movement of water molecules. As the water molecules are disturbed or displaced, they transfer energy to neighboring molecules, causing a ripple effect that propagates as a wave. This movement of water molecules allows the wave to travel across the water surface.
7.
If the object is placed between f and 2f of convex lens, the image will be formed at ____________________.
Correct Answer
B. Beyond 2f
Explanation
When an object is placed between the focal point (f) and twice the focal length (2f) of a convex lens, the image formed is virtual, erect, and magnified. This means that the image appears on the same side as the object, it is upright, and it appears larger than the object. Since the image is virtual and appears on the same side as the object, it is formed beyond 2f of the convex lens. Therefore, the correct answer is "beyond 2f".
8.
The distance between two point charges is 20cm. if the distance is reduced to 10cm, the Coulomb force would become____________________.
Correct Answer
D. Four times
Explanation
When the distance between two point charges is reduced from 20cm to 10cm, the Coulomb force between them becomes four times stronger. This is because the Coulomb force is inversely proportional to the square of the distance between the charges. As the distance is halved, the denominator of the equation becomes one-fourth, resulting in the force becoming four times larger.
9.
In hot summer days reflection of water is seen on the road due to ______________.
Correct Answer
C. Total internal reflection
Explanation
Total internal reflection occurs when light travels from a medium with a higher refractive index to a medium with a lower refractive index, and the angle of incidence is greater than the critical angle. In the case of hot summer days, the air near the road surface is often hotter than the air above it. This temperature difference causes the light to bend as it passes from the cooler air to the hotter air near the road surface, resulting in total internal reflection. This phenomenon creates the illusion of a reflection of water on the road.
10.
What is the induced in the coil when there is a relative motion between the coils of magnet?
Correct Answer
D. Alternating current
Explanation
When there is a relative motion between the coils of a magnet, it induces a current in the coil. This current is known as an induced electromotive force (emf). The induced emf creates an alternating current in the coil, which means the direction of the current constantly changes. Therefore, the correct answer is "alternating current."
11.
The half-life of radium is 1600 years. How much of 120g of radium will be left after 4800 year?
Correct Answer
D. 15g
Explanation
The half-life of radium is 1600 years, which means that after 1600 years, half of the original amount of radium will remain. After another 1600 years, half of that remaining amount will remain, and so on. Since 4800 years is equal to three half-lives of radium, we can calculate that after 4800 years, only one-eighth (1/2 * 1/2 * 1/2) of the original amount will remain. Therefore, 120g * 1/8 = 15g of radium will be left after 4800 years.
12.
The relation between linear expansion and volume expansion is ____________.
Correct Answer
C. β = 3 α
Explanation
The correct answer is β = 3 α. This equation shows the relationship between linear expansion (α) and volume expansion (β). It states that the volume expansion is three times the linear expansion.
13.
A galvanometer is converted into ammeter when we connect a ____________
Correct Answer
D. Low resistance in parallel
Explanation
When a galvanometer is converted into an ammeter, it is done by connecting a low resistance in parallel. This is because an ammeter is used to measure current, and it needs to have a low resistance in order to minimize the voltage drop across it. By connecting a low resistance in parallel with the galvanometer, it allows most of the current to pass through the low resistance, ensuring accurate measurement of the current flowing through the circuit.
14.
The interval of 200µs is equivalent to_____________________.
Correct Answer
C.
Explanation
The interval of 200µs is equivalent to 0.2 sec.
15.
If the capacitance of a capacitor is 10μF and potential difference is 2 volts then charge stored is _______________.
Correct Answer
D.
Explanation
The charge stored in a capacitor can be calculated using the formula Q = CV, where Q is the charge, C is the capacitance, and V is the potential difference. In this case, the capacitance is given as 10 μF and the potential difference is given as 2 volts. Plugging these values into the formula, we get Q = (10 μF)(2 volts) = 20 μC. Therefore, the charge stored is 20 coulomb.
16.
Fahrenheit equivalent of 0K is__________________________.
Correct Answer
B. – 459F°
Explanation
The Fahrenheit scale is based on the freezing and boiling points of water, with 32°F being the freezing point and 212°F being the boiling point. 0K is equivalent to -273.15°C, which is far below the freezing point of water. Since -459°F is the equivalent of -273.15°C, it is the correct Fahrenheit equivalent of 0K.
17.
The work done will be zero when the angle between the force and the distance is ______________________.
Correct Answer
C. 90°
Explanation
When the angle between the force and the distance is 90°, the force and the distance are perpendicular to each other. In this case, the force does not have any component in the direction of the distance. Therefore, the force does not do any work on the object, and the work done is zero.
18.
If mass of both the bodies is 1Kg and distance between their centers is 1m then gravitational force will be:
Correct Answer
B. G
Explanation
The correct answer is G. According to Newton's law of universal gravitation, the gravitational force between two objects is directly proportional to the product of their masses and inversely proportional to the square of the distance between their centers. In this case, since the mass of both bodies is 1Kg and the distance between their centers is 1m, the gravitational force can be represented by the gravitational constant G.
19.
For the propagation of signals in our body _________________energy is used.
Correct Answer
B. Electrical
Explanation
The correct answer is electrical because signals in our body, such as nerve impulses, are transmitted through the use of electrical energy. Electrical signals allow for the rapid and efficient communication between cells and tissues in our body, enabling various physiological processes and functions to occur.
20.
If the zero of the circular scale is below the horizontal line the zero error is to be_______________
Correct Answer
B. Subtracted
Explanation
If the zero of the circular scale is below the horizontal line, it means that the scale is not aligned properly and there is a zero error. To correct this error, we need to subtract the value of the zero error from the readings obtained on the scale. This adjustment ensures that the measurements are accurate and reliable.
21.
When trivalent impurity is added then ________________ is produced.
Correct Answer
C. Hole
Explanation
When a trivalent impurity is added to a material, it introduces an extra electron into the crystal lattice. This extra electron can move freely within the lattice, leaving behind an empty space called a hole. Therefore, the correct answer is "Hole".
22.
When current is passing through a solenoid it becomes______________________
Correct Answer
C. Temporary Magnet
Explanation
When current is passing through a solenoid, it creates a magnetic field around it. This magnetic field can cause the solenoid to behave like a magnet, attracting magnetic materials. However, once the current is turned off, the magnetic field disappears and the solenoid loses its magnetism. Therefore, the solenoid becomes a temporary magnet when current is passing through it.
23.
For scientific notation internationally accepted practice is that there should be ______________digit before the decimal point.
Correct Answer
A. One
Explanation
The internationally accepted practice for scientific notation is to have one digit before the decimal point. This allows for consistent representation of numbers in a concise and standardized manner.
24.
A small steel ball is dropped from a low balcony. Ignoring air resistance, which statement describes its motion?
Correct Answer
A. It falls with constant acceleration.
Explanation
The correct answer is "It falls with constant acceleration." This means that the ball's velocity increases by the same amount every second. Since the question states that air resistance is ignored, the only force acting on the ball is gravity, which causes it to accelerate downwards at a constant rate. As a result, the ball's speed increases as it falls.
25.
Which of the following is a unit of density?
Correct Answer
C.
Explanation
The unit of density is grams per cubic centimeter (g/cm³). Density is a measure of how much mass is contained in a given volume. It is calculated by dividing the mass of an object by its volume. The unit g/cm³ represents the mass of a substance in grams per unit volume in cubic centimeters.