MCQ Questions

Question No. 1

5 × 10^−4 J of work moves 50 μC of charge across the ends of a resistor.

Answer :

a) Calculate the potential difference across the resistor.

b) If the charges take 20 s to travel across the resistor, what is the resistance of the resistor?

Question No. 2

A 0.7 m length of nichrome wire has a diameter of 1.45 mm. The resistivity of nichrome is 1 × 10^−6 Ω·m.

Answer :

a) Calculate the resistance of the wire.

b) If the wire is connected to a 3.0 V cell, determine the current in the wire.

c) If the nichrome wire were cut in half and one of the pieces connected to the same 3.0 V cell, will the current be the same as that in 9b? Explain your answer.

Question No. 3

Two equal lengths of tungsten and aluminium wire of the same diameter are connected in parallel to a 3.0 V cell. Refer to Table 4.6 (page 113). Which of the wires will have the larger current? Explain your answer.

Answer :

Question No. 4

In the circuit in Figure 4.49, the voltmeter reads 12 V. Determine:

Answer :

a) the current through the 60 Ω resistor.

b) the current through the 50 Ω resistor.

c) the heat generated in the 50 Ω resistor in two minutes.

Question No. 5

In the circuit in Figure 4.50, the ammeter reads 1.5 A. Calculate:

Answer :

a) the potential difference across the 8 Ω resistor.

b) the current through the 12 Ω resistor.

c) the power generated in the 4 Ω resistor.

d) the reading on the voltmeter.

Question No. 6

The circuit in Figure 4.51 has three resistors, a fuse (F) with a rating of 4 A and a light bulb marked ‘12 V, 4 W’.

Answer :

a) Determine the current passing through the bulb at its maximum brightness.

b) Calculate the potential difference across the parallel resistors.

c) What is the reading on the voltmeter?

d) If points P and Q in the circuit are joined by a piece of low resistance wire, forming a short circuit, will the fuse blow? Support your answer with calculations.

Question No. 7

Which statement about the properties of electric field lines is incorrect?

Answer :

The field lines are imaginary lines.

The field lines point away from a negative charge and end on a positive charge.

The tangent points in the direction of the force at that point.

The density of the field lines in any region indicates the strength of the electric field at that region.

Question No. 8

The resistance of conductors depends on their: i) resistivity ii) length iii) cross-sectional area. Resistance is directly proportional to:

Answer :

(i), (ii) and (iii)

(i) and (iii) only

(ii) and (iii) only

(i) and (ii) only

Question No. 9

Which energy type does a generator convert into electrical energy?

Answer :

chemical

solar

thermal

mechanical

Question No. 10

If 4 × 10−5 J of work is done to move a charge of 2 μC between two points in an electric field, the potential difference between the two points will be:

Answer :

0.2 V

2 × 10−5 V

8 × 10−5 V

20 V

Question No. 11

A light bulb is connected to a 2 V cell and the power generated in the bulb is P. If the bulb is connected to a 4 V cell (with no change in the resistance of the bulb), the power generated will be:

Answer :

P

2 P

4 P

1 /2 P

Chapter

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