CBSE Class 10 Physics Electricity MCQs Set C

Question. Heat produced in a current carrying wire in 5s is 60J. The same current is passed through another wire of half the resistance. The heat produced in 5s will be
(a) 30 J
(b) 60 J
(c) 15 J
(d) 120 J
Answer : A

Question. The values of mA and μA are:
(a) 10–6 and 10–9 A respectively
(b) 10–3 and 10–6 A respectively
(c) 10–3 and 10–9 A respectively
(d) 10–6 and 10–3 A respectively
Answer : B

Question. The potential at a point is 20V. The work done to bring a charge of 0.5 C from infinity to this point will be ?
(a) 10J
(b) 20J
(c) 5J
(d) 40J
Answer : A

Question. The work done in moving a unit positive charge across two points inan electric circuit is a measure of ?
(a) Potential difference
(b) Current
(c) Resistance
(d) Power
Answer : A

Question. The device used for measuring potential difference is known as ?
(a) Voltmeter
(b) Potentiometer
(c) Ammeter
(d) Galvanometer
Answer : A

Question. A current of 1 A is drawn by a filament of an electric bulb. The number of electrons passing through a cross-section of the filament in 16 seconds would be roughly:
(a) 1020
(b) 1016
(c) 1018
(d) 1023
Answer : A

Question. The free electrons of a metal
(a) Are free to move anywhere in the metal
(b) Do not collide with each other
(c) Do not collide with each other
(d) Are free to escape through the surface
Answer : A

Question. The resistivity of a certain material is 0.6 Ωm.
The material is most likely to be:
(a) an insulator
(b) a superconductor
(c) a conductor
(d) a semiconductor
Answer : D

Question. Electrical resistivity of a given metallic wire depends upon:
(a) Its length
(b) Its thickness
(c) Its shape
(d) Nature of the material
Answer : D

Question. The path of a free electron in a metal is
(a) Zig zag
(b) A straight line
(c) Circular
(d) Parabolic
Answer : A

Question. If the resistance of a certain copper wire is 1 Ω, then the resistance of a similar nichrome wire will be about:
(a) 25 Ω
(b) 30 Ω
(c) 60 Ω
((d) 45 Ω
Answer : C

Question. The current in a wire
(a) Depends on both resistance and potential difference
(b) Depends only on the potential difference applied
(c) Depends only on the resistance of the wire
(d) Does not depend on resistance and potential difference
Answer : D

Question. When there is an electric current passing through a wire, the particles moving are
(a) Electrons
(b) Protons
(c) Atoms
(d) Ions
Answer : A

Question. Unit of electric power may also be expressed as:
(a) volt-ampere
(b) kilowatt-hour
(c) watt-second
(d) joule-second
Answer : A

Question. A positive charge released from rest
(a) Moves towards the regions of lower potentia
(b) Moves towards the regions of higher potential
(c) Moves towards the regions of equal potential
(d) Does not move
Answer : A

Question. The resistance of a resistor is reduced to half of its initial value. In doing so, if other parameters of the circuit remain unchanged, the heating effects in the resistor will become:
(a) two times
(b) half
(c) one-fourth
(d) four times
Answer : A

Question. Three equal resistances when combined in series are equivalent to 90w. Their equivalent resistance when combined in parallel will be
(a) 10 W
(b) 270 W
(c) 30 W
(d) 810 W
Answer : A

Question. When a 4 V battery is connected across an unknown resistor there is a current of 100 mA in the circuit. The value of the resistance of the resister is:
(a) 4Ω
(b) 40Ω
(c) 400Ω
(d) 0.4 Ω
Answer : B

Question. An battery is used to
(a) Maintain a potential difference
(b) Measure electric current
(c) Measure electric potential
(d) Safeguard against short - circuit
Answer : A

Question. Ohms law relates potential difference with
(a) Current
(b) Time
(c) Power
(d) Energy
Answer : A

Question. Which of the following is an ohmic resistor
(a) Nichrome
(b) Diamond
(c) Germanium
(d) Diode
Answer : A

Question. At the time of short circuit, the electric current in the circuit:
(a) vary continuously
(b) does not change
(c) reduces substantially
(d) increases heavily
Answer : D

Question. Calculate the length of aluminium wire of area of cross-section 1 mm² whose resistance is 
1.56 × 10^–2 W. Given, resistivity of aluminium is 2.6 × 10^–8 W m.
(a) 60 mm
(b) 60 cm
(c) 60 m
(d) 6 m 
Answer : B

Question. Consider a simple circuit containing a battery and three identical incandescent bulbs A, B and C. Bulb A is wired in parallel with bulb B and this combination is wired in series with bulb C. What would happen to the brightness of the other two bulbs if bulb A were to burn out? 
(a) Only bulb B would get brighter.
(b) Both A and B would get brighter.
(c) Bulb B would get brighter and bulb C would get dimmer.
(d) There would be no change in the brightness of either bulb B or bulb C
Answer : C

Question. The equivalent resistance between the points A and B as shown in the figure is 

(a) 6 W
(b) 8 W
(c) 16 W
(d) 24 W
Answer : B

Question. A piece of aluminium of finite length is drawn or stretched such that to reduce its diameter to one fourth its original value, its resistance will become 
(a) 256 times
(b) four times
(c) eight times
(d) sixteen times
Answer : A

Question. The normal positions of the pointers of the two ammeters A₁ and A₂, and two voltmeters V₁ and V₂ available in the laboratory are shown in figure. For verifying Ohm’s law the student should select 9 D
(a) ammeter A₁ and voltmeter V₁
(b) ammeter A₁ and voltmeter V₂
(c) ammeter A₂ and voltmeter V₁
(d) ammeter A₂ and voltmeter V₂
Answer : D

Question. In an electrical circuit, three incandescent bulbs A, B and C of rating 40 W, 60 W and 100 W respectively are connected in parallel to an electric source. Which of the following is likely to happen regarding their brightness? 
(a) Brightness of all the bulbs will be the same
(b) Brightness of bulb A will be the maximum
(c) Brightness of bulb B will be more than that of A
(d) Brightness of bulb C will be less than that of B
Answer : C

Question. The effective resistance between A and B is 

(a) r₁ + r₂
(b) r1 − r2
(c) 1/r1 + 1/r₂
(d) r₁ r₂/r1 + r₂
Answer : D

Question. There are three copper wires of lengths and cross-sectional areas (L, A), (2 L, A/2), (L/2, 2 A). Resistivity is 
(a) minimum of wire of cross-sectional area A/2
(b) minimum of wire of cross-sectional area A
(c) minimum of wire of cross-sectional area 2A
(d) same in all the three cases.
Answer : D

Question. 10,000 alpha-particles per minute are passing through a straight tube of radius r. 
The resulting electric current is approximately
(a) 0.5 × 10–16 A
(b) 2 × 1012 A
(c) 0.5 × 1012 A
(d) 2 × 10–12 A
Answer : A

Question. For ensuring dissipation of same energy in all three resistors (R₁, R₂, R₃) connected as shown in figure, their value must be related as 
 
(a) R₁ = R₂ = R₃
(b) R₂ = R₃ and R₁ = 4R₂
(c) R₂ = R₃ and R₁ = 1/4 R₂
(d) R₁ = R₂ + R₃
Answer : C

Question. To determine the equivalent resistance of a series combination of two resistors R₁ and R₂, a student arrange the following set up. 

Which one of the following statements will be true for this circuit ? It gives
(a) incorrect reading for current I as well as potential difference V
(b) correct reading for current I but incorrect reading for potential difference V
(c) correct reading for potential difference V but incorrect reading for current I
(d) correct reading for both I and V.
Answer : B

Question. If current through a resistance is increased by 100%, simultaneously reducing resistance value to 25%, the new power dissipated will be 
(a) same
(b) increased by 100%
(c) decreased by 400%
(d) increased by 400%
Answer : A

Question. The amount of heat energy produced in 5 minutes by an electric heater rated at 1000 W is 
(a) 2 × 105 J
(b) 3 × 105 J
(c) 4 × 105 J
(d) 300 J
Answer : B

Question. A current of 4.8 A is flowing in a conductor. 
The number of electrons passing per second through the conductor will be
(a) 3 × 10²⁰
(b) 76.8 × 10²⁰
(c) 7.68 × 10^–19
(d) 3 × 10¹⁹
Answer : D

Question. In an experiment on finding equivalent resistance of two resistors in series, four students draw up circuits. Which one is correct? 


Answer : C