1.
If a number of resistors are connected in parallel, then the reciprocal of total resistance is equal to
Correct Answer
B. Sum of the reciprocal of individual resistances
Explanation
When resistors are connected in parallel, the total resistance decreases. The reciprocal of resistance is conductance, which increases when resistances are connected in parallel. Therefore, the sum of the reciprocal of individual resistances is equal to the reciprocal of the total resistance.
2.
The unit of electrical energy is/are
Correct Answer
D. All of these
Explanation
The unit of electrical energy can be expressed in Joules, which is the standard unit for energy. It can also be measured in Watt-seconds, as power is the rate at which energy is consumed or produced. Additionally, electrical energy can be quantified in kilowatt-hours, which is commonly used to measure electricity consumption in households and businesses. Therefore, all of the given options are correct units for measuring electrical energy.
3.
If a current of 5A flows through a resistor of 12 ohms then the power developed and the energy dissipated in 2 minutes is
Correct Answer
A. 300 W, 36000 J
Explanation
When a current of 5A flows through a resistor of 12 ohms, we can calculate the power developed using the formula P = I^2 * R, where P is the power, I is the current, and R is the resistance. Substituting the given values, we get P = 5^2 * 12 = 300W.
To calculate the energy dissipated, we use the formula E = P * t, where E is the energy, P is the power, and t is the time. Substituting the given values of P = 300W and t = 2 minutes (which is equivalent to 120 seconds), we get E = 300 * 120 = 36000J.
Therefore, the correct answer is 300W, 36000J.
4.
According to Kirchoff’s voltage law,
Correct Answer
C. Algebraic sum of e.m.f’s plus algebraic sum of voltage drops is equal to zero
Explanation
According to Kirchoff's voltage law, the algebraic sum of all the e.m.f's (electromotive forces) in the circuit is equal to the algebraic sum of all the voltage drops in the circuit. This means that the total energy gained from the e.m.f's is equal to the total energy lost through the voltage drops in the circuit. Therefore, the correct answer is that the algebraic sum of e.m.f's plus the algebraic sum of voltage drops is equal to zero.
5.
True or False? In a series circuit, the amount of current is the same through any component in the circuit
Correct Answer
A. True
Explanation
In a series circuit, the amount of current is the same through any component in the circuit. This is because in a series circuit, the components are connected one after another, forming a single pathway for the current to flow. As a result, the current flowing through each component is equal since there are no alternate paths for the current to divide or change. Therefore, the statement that the amount of current is the same through any component in a series circuit is true.
6.
How many paths do the electrons have to flow in a series circuit?
Correct Answer
B. 1
Explanation
In a series circuit, all the components are connected in a single loop, meaning there is only one path for the electrons to flow. The current flows through each component in the circuit sequentially, without any branches or alternate paths. Therefore, the correct answer is 1.
7.
The loads in a series circuit must __________ the available voltage.
Correct Answer
C. Share
Explanation
In a series circuit, the loads must "share" the available voltage. This means that the voltage across each load in the circuit will be the same, as the total voltage of the circuit is divided equally among the loads. This allows for a consistent flow of current through each load, ensuring proper functioning of the circuit. The other options, "fuel" and "power," are not relevant to the concept of voltage distribution in a series circuit.
8.
In any network of wires carrying currents, the algebraic sum of all currents meeting at a point is equal to
Correct Answer
B. Zero
Explanation
The correct answer is "Zero". According to Kirchhoff's current law, the algebraic sum of all currents meeting at a point in a network of wires carrying currents is always zero. This means that the sum of all incoming currents is equal to the sum of all outgoing currents at that point. This law is based on the principle of conservation of charge, stating that the total charge entering a junction must equal the total charge leaving the junction.
9.
The specific resistance of a material is
Correct Answer
B. Directly proportional to the area of cross section and inversely proportional to the length of material
Explanation
The specific resistance of a material is directly proportional to the area of cross section because a larger cross-sectional area provides more space for the flow of electric current, reducing resistance. It is inversely proportional to the length of the material because a longer length increases the path that the current must travel, resulting in higher resistance.
10.
There are three main rules that apply to the series circuit. Which of the following is one of the rules?
Correct Answer
D. All of the above
Explanation
In a series circuit, the sum of the potential drops equals the potential rise of the source because the total voltage supplied by the source is divided among the components. The current is the same everywhere in the series circuit because there is only one path for the current to flow. The total resistance of the circuit is equal to the sum of the individual resistances because resistors in a series circuit add up to create a larger overall resistance. Therefore, all of the above statements are rules that apply to a series circuit.