CBSE Class 10 Physics Electricity MCQs Set 07

Question: What is the minimum resistance which can be made using five resistors each of (1/5) Ω?
a) (1/5) Ω
b) (1/25) Ω
c) (1/10) Ω
d) 25 Ω
Answer: b

Question: A 24 V potential difference is applied across a parallel combination of four 6 Ω resistors. The current in each resistor is:
a) 1 A
b) 4 A
c) 16 A
d) 36 A
Answer: b

Question: The length of a wire is doubled. By what factor does the resistance change?
a) 4 times as large
b) Twice as large
c) Unchanged
d) Half as large
Answer: d

Question: A wire of resistance R is cut into ten equal parts which are then joined in parallel. The new resistance is:
a) 0.01 R
b) 0.1 R
c) 10 R
d) 100 R
Answer: a

Question: What is the maximum resistance which can be made using five resistors each of (1/5) Ω?
a) (1/5) Ω
b) 10 Ω
c) 5 Ω
d) 1 Ω
Answer: d

Question: 100 J of heat is produced each second in a 4 Ω resistance. The potential difference across the resistor is:
a) 20 V
b) 10 V
c) 5 V
d) 15 V
Answer: a

Question: The ratio of resistances of two bulbs rated 40 Ω, 220 V and 20 Ω, 100 V respectively is:
a) 1 : 2
b) 2 : 1
c) 1 : 1
d) 1 : 3
Answer: b

Question: How much work is done in moving a charge of 2 C from a point of 118 V to a point of 128 V?
a) 20 J
b) 30 J
c) 40 J
d) 10 J
Answer: a

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: A cylindrical rod is reformed to twice its length with no change in its volume. If the resistance of the rod was R, the new resistance will be:
a) R
b) 2R
c) 4R
d) 8R
Answer: c

Question: If the current I through a resistor is increased by 100% (assume that temperature remains unchanged), the increase in power dissipated will be:
a) 100%
b) 200%
c) 300%
d) 400%
Answer: c

Question: Two unequal resistances are connected in parallel. Which of the following statements is true?
a) Current is same in both
b) Current is larger in higher resistance
c) Voltage-drop is same across both
d) Voltage-drop is lower in lower resistance
Answer: c

Question: A cylindrical conductor of length l and uniform area of cross-section A has resistance R. Another conductor of length 2l and resistance R of the same material has area of cross-section:
a) A/2
b) 3A/2
c) 2A
d) 3A
Answer: c

Question: 20 coulomb charge is flowing in 0.5 second from a point in an electric circuit. The value of current in amperes will be:
a) 10
b) 40
c) 0.005
d) 0.05
Answer: b

Question: A letter A is constructed of a uniform wire of resistance 1 Ω/cm. The sides of the letter are 20 cm and the cross piece in the middle is 10 cm long. The resistance between the ends of the legs will be:
a) 32.4 Ω
b) 28.7 Ω
c) 26.7 Ω
d) 24.7 Ω
Answer: c

Question: What is the current through a 5.0 Ω resistor if the voltage across it is 10 V?
a) Zero
b) 0.5 A
c) 2.0 A
d) 5.0 A
Answer: c

Question: A piece of wire of resistance R is cut into five equal parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R₁, then the ratio R/R₁ is:
a) 1/25
b) 1/5
c) 5
d) 25
Answer: d

Fill in the Blanks :

Question: ………….. is a property that resists the flow of electrons in a conductor.
Answer: Resistance

Question: Electrical power = (Potential difference)2/……….
Answer: cresistance

Question: A fuse is connected in ………. to the ………. wire.
Answer: Series, live

Question: The resistance of a conductor depends directly on its …………., inversely on its …………….., and also directly proportioned on the ………….. of the conductor.
Answer: length, area of cross-section, resistivity

Question: Power transmission is carried out at high ………. and low …….. .
Answer: Voltage, current

Question: 1 volt × 1 coulomb = …………..
Answer: joule

Question: The ………. reaction within the cell generates the potential difference between its two terminals that sets the ………. in motion to flow the current through a resistor.
Answer: chemical

Question: The S.I. unit of resistance is ……………..
Answer: ohm (Ω)

Question: Copper is a preferred material for making wire because of its low ……….
Answer: Resistivity

Question: The electrical energy dissipated in a resistor is given by W = ……….
Answer: VxI xt

True / False :

Question: The resistance of a wire is directly proportional to length.
Answer: True

Question: When a metallic conductor is heated the atoms in the metal vibrate with greater amplitude and frequency.
Answer: True

Question: The quantity of charge flowing through a point multiplied by time is a current.
Answer: False

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

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

Question: The sun is visible two minutes before the actual sunrise due to atmospheric refraction.
Answer: True

Question: The focal length of a given lens depends on the surrounding medium.
Answer: True

Question: When a metallic conductor is heated the atoms in the metal vibrate with greater amplitude and frequency.
Answer: True

Question: The solar spectrum in general is an absorption spectrum.
Answer: False

Question: Ohm’s law is a relation between the power used in a circuit to the current and the potential difference.
Answer: False

Match the Following :

Question: Match the Following

  Column I                     ​​​​​​​       Column II
(A) Ohm                              (p) PL/A
(B) Resistance                    (q) 1volt/1 ampere
(C) Resistivity                      (r) zero resistance
(D) Super conductor           (s) ohm-meter
Answer: a-q, B-p, C-s, D-r

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

  Column I           ​​​​​​​          ​​​​​​​          ​​​​​​​          ​​​​​​​       Column II
(A) Resistance of resistance box             (p) R/2+6
(B) Resistance between a and c             (q) 5/8 R
(C) Resistance between b and d r           (r) R
Answer: a-q, B-r, C-p, D-s

Question:

  Column I           ​​​​​​​          ​​​​​​​          Column II
(A) Ohm                              (p) ρL/A
(B) Resistance                   (q) 1 volt/1 ampere
(C) Resistivity                     (r) zero resistance
(D) Super conductor           (s) ohm-meter
Answer: (A) → (q); (B) → (p); (C) → (s); (D) → (r)