Electric Resistance and Ohm’s Law MCQ Type Questions for ISC Class-12 Ch-5 Physics . These MCQ / Objective Type Questions is based on latest reduced syllabus according 2021-22 session on bifurcated pattern. Main motto of MCQ Type Question is cracking the next upcoming exam of council. Visit official website **CISCE** for detail information about ISC Board Class-12 Physics.

** ISC Class-12 Ch-5 Electric Resistance and Ohm’s Law MCQ Type Que****stions **

Board | ISC |

Class | 12th (XII) |

Subject | Physics |

Chapter-5 | Electric Resistance and Ohm’s Law |

Syllabus | on bifurcated syllabus (after reduction) |

Session | 2021-22 |

Topic | MCQ / Objective Type Question |

**Chapter-5 Electric Resistance and Ohm’s Law MCQ Type Questions for ISC Class-12 Physics**

**Question 1: ****If the conductor resistance is 50 ohm and the current passing through it is 5 A. What is the value of potential difference?**

(a) 150 V

(b) 250 V

(c) 50 V

(d) 15 V

**Answer: (b) 250 V**

**Question 2: When the length of the conductor is doubled and the area of cross-section remains the same then its resistance**

(a) Remains the same

(b) Will be doubled

(c) Will become half

(d) Will increase by four times

**Answer: (b) Will be doubled**

**Question 3: The current passing through a resistor in a circuit is 1 A when the voltage across the same resistor is 10 V. What is the value of current when the voltage across the resistor is 8 V**

(a) 0.8 A

(b) 8 A

(c) 80 A

(d) 18 A

**Answer: (a) 0.8 A**

**Question 4: **The number of electrons that constitute 1 A of current is:

(a) 6.25 × 10^{16}

(b) 6.25 × 10^{17}

(c) 6.25 × 10^{18}

(d) 6.25 × 10^{19}

**Answer: (c) 6.25 × 10 ^{18}
**

**Question 5: **How many different resistances are possible with two equal resistors?

(a) 2

(b) 3

(c) 4

(d) 5

**Answer: (b) 3
**

**Question 6: **Given three equal resistors, how many different combinations (taken all of them together) can be made?

(a) 3

(b) 4

(c) 5

(d) 6

**Answer: (b) 4
**

**Question 7: **An electric heater is connected to the voltage supply. After few seconds, current gets its steady value then its initial current will be

(a) equal to its steady current

(b) slightly higher than its steady current

(c) slightly less than its steady current

(d) zero

**Answer: (b) slightly higher than its steady current
**

**Question 8: I**n the series combination of two or more than two resistances

(a) the current through each resistance is same.

(b) the voltage through each resistance is same.

(c) neither current nor voltage through each re-sistance is same.

(d) both current and voltage through each resis¬tance are same.

**Answer: (a) the current through each resistance is same.
**

**Question 9: ****If a current of 5 Amperes flows through the conductor. The number of electrons per second will is**

(a) 1.6 x 10^{-19}

(b) 3.12 x 10^{19}

(c) 4 x 10^{19}

(d) 7.68 x 10^{20}

**Answer: (b) 3.12 x 10 ^{19}**

**Question 10: Ohm’s law is true for**

(a) Metallic conductors at low temperature

(b) Metallic conductors at high temperature

(c) For electrolytes, when current passes through them

(d) For diode when current flows

**Answer: (a) Metallic conductors at low temperature**

**Question 11: **The speed at which tjie current travels in a conductor is nearly:

(a) 3 × 10^{4} ms^{-1}

(b) 3 × 10^{6} ms^{-1}

(c) 3 × 10^{8} ms^{-1}

(d) 3 × 10^{10} ms^{-1}

**Answer: (a) 3 × 10 ^{4} ms^{-1}**

**Question 12: **The resistance of a human body is about:

(a) 12 Ω

(b) 120 Ω

(c) 12 KΩ

(d) 120 MΩ

**Answer: (c) 12 KΩ
**

**Question 13: Combine three resistors 5 Q, 4.5 Q and 3 Q in such a way that the total resistance of this combination is maximum**

(a) 12.5 Q

(b) 13.5 Q

(c) 14.5 Q

(d) 16.5 Q

**Answer: (a) 12.5 Q
**

**Question 14: In parallel combination of n cells, we obtain**

(a) more voltage

(b) more current

(c) less voltage

(d) less current

**Answer: (b) more current
**

**Question 15: ****An example of non-ohmic resistance is**

(a) Diode

(b) Tungsten wire

(c) Carbon resistance

(d) Copper wire

**Answer: (a) Diode**

**Question 16: In a conductor, if 6-coulomb charge flows for 2 seconds. The value of electric current will be**

(a) 3 ampere

(b) 3 volts

(c) 2 amperes

(d) 2 volts

**Answer: 3 amperes**

**Question 17: An EMF source of 8.0 V is connected to a purely resistive electrical appliance. An electric current of 2.0 A flows through it. What is the resistance offered by the electrical appliances?**

(a) 4 ohm

(b) 6 ohm

(c) 2 ohm

(d) 3 ohm

**Answer: (a) 4 ohm**

**Question 18: A potential difference of 10 V is applied across a conductor whose resistance is 2.5 ohm. What is the value of current flowing through it?**

(a) 4 amperes

(b) 2 amperes

(c) 6 amperes

(d) 10 amperes

**Answer: (a) 4 amperes**

**Question 19: **The specific resistance of a rod of copper as compared to that of thin wire of copper is :

(a) less

(b) more

(c) same

(d) depends upon the length and area of cross-section of the wire

**Answer: (c) same
**

**Question 20: **A wire of resistance 3 Ω is cut into three pieces, which are then joined to form a triangle. The equivalent resistance between any corners of the triangle is :

(a) 2/3 Ω

(b) 3/2 Ω

(c) 1/2 Ω

(d) 1/3 Ω

**Answer: (a) 2/3 Ω
**

**Question 21: **Siemen is the unit of:

(a) resistance

(b) conductance

(c) specific conductance

(d) None of these

**Answer: (b) conductance
**

**Question 22: **How much electric energy is consumed by a 100 W lamp used for 6 hours everyday for 30 days?

(a) 18 kJ

(b) 18 kWh

(c) 1.8 J

(d) None of these

**Answer: (b) 18 kWh
**

**Question 23: In a Wheatstone bridge if the battery and galvanometer are interchanged then the deflection in galvanometer will**

(a) change in previous direction

(b) not change

(c) change in opposite direction

(d) none of these.

**Answer: (b) not change
**

**Question 24: In a potentiometer of 10 wires, the balance point is obtained on the 7 ^{th} wire. To shift the balance point to 9th wire, we should**

(a) decrease resistance in the main circuit.

(b) increase resistance in the main circuit.

(c) decrease resistance in series with the cell whose emf is to be measured.

(d) increase resistance in series with the cell whose emf is to be determined.

**Answer: (d) increase resistance in series with the cell whose emf is to be determined.**

**Question 25: ****If the conductor resistance is 50 ohm and the current passing through it is 5 A. What is the value of potential difference?**

(a) 150 V

(b) 250 V

(c) 50 V

(d) 15 V

**Answer: (b) 250 V**

**Question 26: The length of a conductor is halved. Its resistance will be :**

(a) halved

(b) doubled

(c) unchanged

(d) quadrupled

**Answer: (a) halved
**

**Question 27: **How much electric energy is consumed by a 100 W lamp used for 6 hours everyday for 30 days?

(a) 18 kJ

(b) 18 kWh

(c) 1.8 J

(d) None of these

**Answer: (b) 18 kWh**

**Question 28: **Suppose H_{1} is the heat generated per second in the filament of a 100 W, 250 V lamp and H_{2} is the heat generated in the filament of a 200 W, 250 V lamp. Then H_{1}/H_{2} is equal to:

(a) 1

(b) 2

(c) 1/2

(d) 1/4

**Answer: (d) 1/4**

**Question 29: A charge is moving across a junction, then**

(a) momentum will be conserved.

(b) momentum will not be conserved.

(c) at some places momenturii will be conserved and at some other places momentum will not be conserved.

(d) none of these.

**Answer: (d) none of these.**

**Question 30: The I-V characteristics shown in figure represents
**(a) ohmic conductors

(b) non-ohmic conductors

(c) insulators

(d) superconductors

**Answer: (b) non-ohmic conductors
**

**Question 31: **Two wires of copper are of the same length but’have different diameters. When they are connected in series across a battery, the heat generated is H_{1} When connected in parallel across the same battery, the heat generated during the same time is H_{2} Then :

(a) H_{1} = H_{2}

(b) H_{1} < H_{2}

(c) H_{1} > H_{2}

(d) H_{1} > H_{2}

**Answer: (b) H _{1} < H_{2}**

**Question 32: **In questions 135, w hen the wires are connected in series, the heat produced in the thinner wire is H_{1} and that in the thicker wire is H_{2}. Then :

(a) H_{1} = H_{2}

(b)H_{1} < H_{2}

(c) H_{1} > H_{2}

(d) H_{1} > H_{2}

**Answer: (b) H _{1} < H_{2}**

**Question 33: A 5 A fuse wire can with stand a maximum power of 1 W in circuit. The resistance of the fuse wire is:**

**(a) 0.2 Ω
(b) 5 Ω
(c) 0.4 Ω
(d) 0.04 Ω**

**Answer: (d) 0.04 Ω**

**Question 34: **When three identical bulbs of 60 W, 200 V rating are connected in series to a 200 V supply, the power drawn by them will be:

(a) 20 W

(b) 60 W

(c) 180 W

(d) 10 W

**Answer: (a) 20 W
**

**Question 35: **n resistances, each of R Ω, are connected in parallel gives an equivalent resistance of R Ω. If these resistances were , connected in series, the combination would have a resistance in Ω is equal to

(a) n²R

(b) R/n²

(c) R/n

(d) nR

**Answer: (a) n²R
**

**Question 36: The resistivity of alloy manganin is**

(a) Nearly independent of temperature

(b) Increases rapidly with increase in temperature

(c) Decreases with increase in temperature

(d) Increases rapidly with decrease in temperature

**Answer: (a) Nearly independent of temperature
**

**Question 37: Ohm’s law is valid when the temperature of conductor is :**

(a) very low

(b) very high

(c) varying

(d) constant

**Answer: (d) constant**

**Question 38: **The smallest resistance that can be obtained by the combination of n resistors each resistance r is :

(a) r/n

(b) nr

(c) n/r

(d) n²r

**Answer: (a) r/n
**

**Question 39: **Which of the following has a negative temperature coefficient of resistance ?

(a) Tungsten

(b) Carbon

(c) Nichrome

(d) Platinum

**Answer: (b) Carbon
**

**Question 40: **A uniform w ire connected across a supply produces heat H per second. If wire is cut into three equal parts and all the parts are connected in parallel across the same supply, the heat produced per second will be :

(a) H/9

(b) 9 H

(c) 3 H

(d) H/3

**Answer: (d) H/3**

**Question 41: **In India electricity is supplied fordomestic use at 220 V. It is supplied at 110 V in U.S.A. If the resistance of a 60 W bulb use in India is R. the resistance of a 60 W bulb for use in USA will be:

(a) 2 R

(b) R

(c) R/2

(d) R/4

**Answer: (d) R/4**

**Question 42: In the following figure represents a balanced Wheatstone bridge circuit. What is the value of X ?
**

(a) 15 Ω

(b) 20 Ω

(c) 25 Ω

(d) 30 Ω

**Answer: (c) 25 Ω
**

**Question 43: **Thermo electricity was discovered by:

(a) Joule

(b) Peitier

(c) Thomson

(d) Seebeck

**Answer: (d) Seebeck**

**Question 44: **Thermo emf is the order of:

(a) 10 V

(b) 10^{-3} V

(c) 10^{-6} V

(d) 10^{-12} V

**Answer: (c) 10 ^{-6} V
**

**Question 45: In following figure shows currents in a part of electrical circuit, then the value of/(in ampere) is given by :
**

(a) 0.3 A

(b) 0.5 A

(c) 1.3 A

(d) None of these

**Answer: (a) 0.3 A
**

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