CBSE Class 10 Physics Electricity MCQs Set F

Question: A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross-section of the filament in 16 seconds would be roughly:
a) 10²⁰
b) 10¹⁰
c) 10¹⁸
d) 10²³
Answer: a

Question: Kilowatt hour is the unit of
a) Electric power
b) Electric resistance
c) Electric potential
d) Electric energy
Answer: d

Question: Electric power is given by
a) P = V/I
b) P = I/V
c) P = I/VI
d) P = VI
Answer: d

Question: How is fuse connected to the electric device?
a) Series
b) Parallel
c) Both
d) None
Answer: a

Question: Three resistances of 4Ω, 5Ω and 20Ω are connected in parallel. Their combined resistance is
a) 2Ω
b) 4Ω
c) 5Ω
d) 20Ω
Answer: a

Question: Which electrical component protects from short circuiting?
a) Fuse
b) Resistor
c) Electric plug
d) Switch
Answer: a

Question: Watt is the unit of
a) Electric current
b) Electric energy
c) Electric power
d) Potential difference
Answer: c

Question: The practical unit of electrical energy
a) Watt
b) Kilowatt
c) Kilowatt hour
d) Kilo Joule
Answer: c

Question: A small heating element connected to a 10 V battery draws a current of 5 A. How much electric power is supplied to the heater?
a) 15 W
b) 25 W
c) 2 W
d) 50 W
Answer: d

Question: The SI unit of electric power is
a) Coulomb
b) Ampere
c) Joule
d) Watt
Answer: d

Question: When a current of I ampere is passed through a resistor of R ohm for t seconds, then the amount of heat produced is
a) H = I²Rt Cal
b) H = I²Rt Kcal
c) H = I²Rt joule
d) H = I²Rt/4.18 joule
Answer: c

Question: Three resistors of resistances R₁, R₂ and R₃ are connected in series. If I is the current passing through R₁
a) 1:1
b) 1:2
c) 1:3
d) 1:4
Answer: a

Question: How many joules are there in 1 kilowatt hour?
a) 3.6 × 10³
b) 3.6 × 10⁴
c) 3.6 × 10⁵
d) 3.6 × 10⁶
Answer: d

Question: A __________ consists of a piece of wire made of metal or an alloy (37% lead, 63% tin).
a) Fuse
b) Resistor
c) Electric plug
d) Switch
Answer: a

Question: What is the current rating for the circuit used for bulbs, fans, etc.?
a) 5 A
b) 10 A
c) 15 A
d) 20 A
Answer: a

Question: State which of the following is correct?
a) Joule = Coulomb × Volt
b) Joule = Coulomb/Volt
c) Joule = Volt/Ampere
d) Joule = Ampere/Volt
Answer: a

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 direction of electric current is taken as __________ to the direction of the flow of electrons.
a) Same
b) Opposite
c) Both
d) None
Answer: b

Question: Three resistances of 1Ω each are connected to form a triangle. The resistance between any two terminals is
a) 3Ω
b) ½Ω
c) ⅔Ω
d) 3/2Ω
Answer: c

Question: The resistivity does not change if:
a) The material is changed
b) The temperature is changed
c) The shape of the resistor is changed
d) Both material and temperature are changed
Answer: c

Assertion And Reason Based Questions :

(a) Both assertion (A) and reason (R) are true and reason (R) is the correct explanation of assertion (A).
(b) Both assertion (A) and reason (R) are true but reason (R) is not the correct explanation of assertion (A).
(c) Assertion (A) is true but reason (R) is false.
(d) Assertion (A) is false but reason (R) is true.
(e) Both Assertion and Reason are false.

Question:
Assertion : If r 1 and r 2 be the resistivity of the materials of two resistors of resistances R1 and R2 respectively and R1 > R2 .
Reason : The resistance R = P,1/A ⇒ r1 > r2 if R1 > R2
Answer: c

Question:
Assertion : Copper is used to make electric wires.
Reason : Copper has very low electrical resistance.
Answer: a

Question:
Assertion : Silver is not used to make electric wires.
Reason : Silver is a bad conductor.
Answer: c

Question:
Assertion : Wire A is thin in comparison to wire B of same material same length then resistance of wire A is greater than resistance of wire B.
Reason : Resistivity of wire A is greater than resistance of wire B.
Answer: c

Question:
Assertion : A voltmeter and ammeter can be used together to measure resistance but not power.
Reason : Power is proportional to voltage and current.
Answer: e

Question:
Assertion : A resistor of resistance R is connected to an ideal battery. If the value of R is decreased, the power dissipated in the circuit will increase.
Reason : The power dissipated in the circuit is directly proportional to the resistance of the circuit.
Answer: c

Question:
Assertion : The 200 W bulbs glow with more brightness than 100 W bulbs.
Reason : A 100 W bulb has more resistance than 200 W bulb.
Answer: a

Question:
Assertion : The resistivity of conductor increases with the increasing of temperature.
Reason : The resistivity is the reciprocal of the conductivity.
Answer: b

Question:
Assertion : If a graph is plotted between the potential difference and the current flowing, the graph is a straight line passing through the origin.
Reason : The current is directly proportional to the potential difference.
Answer: a

Question:
Assertion : The equation V = Ri does not apply to those conducting. devices which do not obey Ohm’s law.
Reason : V = RI is a statement of Ohm’s law.
Answer: c

Fill in the Blanks :

Question: Electric energy is produced by the …….. of charges.
Answer: Separation

Question: Physical quantity represented by coulomb per second is ………. .
Answer: Electric current

Question: The alloy which is used for making the filament of bulbs is ………
Answer: Tungsten

Question: Rate at which electric work is done is called ………
Answer: Electric power

Question: If there is no current, a voltmeter connected across a resistor will register………………… voltage.
Answer: zero

Question: The potential difference across the ends of a resistor is …………… to the current through it, provided its ……………….. remains the same.
Answer: directly proportional, temperature

Question: The resistance of a semiconductor …….. with increase in temp.
Answer: decreases

True / False :

Question: The resistivity of all pure metals increases with the rise in temperature.
Answer: True

Question: The resistance of a wire is directly proportional to area.
Answer: False

Question: The resistivity of a wire is directly proportional to cross-sectional area.
Answer: True

Question: In parallel combination, the reciprocal of equivalent resistance is the sum of the reciprocal of individual resistance.
Answer: True

Question: One kilowatt is equal to 10 horse power.
Answer: False

Question: The reciprocal of resistance is called specific
Answer: False

Match the Following :

Question:

 Column I                       ​​​​​​​           ​​​​​​​          ​​​​​​Column II
1. Filament of electrical bulb           (a) Copper
2. Heating elements                        (b) Lead-tin alloy
3. Connection wire                          (c) Tungsten
4. Fuse wire                                    (d) Nichrome
Answer: 1-(c), 2-(d), 3-(a), 4-(b)

Question: Column II gives name of material use for device given in column I

Column I Column II
(A) Resistance of resistance box             (p) tungsten
(B) Fuse wire                                           (q) maganin
(C) Bulb                                                   (r) tin-lead alloy
(D) Insulator                                             (s) glass
Answer: (A) → q; (B) → r; (C) → p; (D) → s