3. CURRENT ELECTRICITY ( Objective Question Answer 2022 )

Physics English Medium

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Class 12th Model SET 2023 Download

1. The speed at which the current travels in a conductor is nearly :

(A) 3 x 10⁴ ms^-1
(B) 3 x 10⁶ ms^-1
(C) 3 x 10⁸ ms^-1
(D) 3 x 10¹⁰ ms^-1

Answer ⇒ A

2. The resistance of a human body is about :

(A) 12 Ω
(B) 120 Ω
(C) 12 KΩ
(D) 120 MΩ

Answer ⇒ C

3. The number of electrons that constitute 1 A of current is :

(A) 6.25 x 10¹⁶
(B) 6.25 x 10¹⁷
(C) 6.25 x 10¹⁸
(D) 6.25 x 10¹⁹

Answer ⇒ C

4. How many different resistances are possible with two equal resistors ?

(A) 2
(B) 3
(C) 4
(D) 5

Answer ⇒ B

5. 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

6. Specific resistance of all metals is mostly affected by :

(A) temperature
(B) pressure
(C) magnetic field
(D) volume

Answer ⇒ A

7. The example of a non-ohmic resistance is :

(A) copper wire
(B) filament lamp
(C) carbon resistor
(D) diode

Answer ⇒ D

8. The length of a conductor is halved. Its resistance will be :

(A) halved
(B) doubled
(C) unchanged
(D) quadrupled

Answer ⇒ A

9. In the above question, the conductance :

(A) halved
(B) doubled
(C) unchanged
(D) quadrupled

Answer ⇒ B

10. Siemen is the unit of :

(A) resistance
(B) conductance
(C) specific conductance
(D) None of these

Answer ⇒ B

11. 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 H₁ When connected in parallel across the same battery, the heat generated during the same time is H₂ Then :

(A) H₁ = H₂
(B) H₁ < H₂
(C) H₁ > H₂
(D) H₁ > H₂

Answer ⇒ B

12. In questions 135, when the wires are connected in series, the heat produced in the thinner wire is H₁ and that in the thicker wire is H₂ Then :

(A) H₁ = H₂
(B) H₁ < H₂
(C) H₁ > H₂
(D) H₁ ≥ H₂

Answer ⇒ C

13. Kirchhoff’s first and second laws for electrical circuits are consequences of :

(A) conservation of energy
(B) conservation of electrical charge and energy respectively
(C) conservation of electric charge
(D) neither conservation of energy nor electric charge

Answer ⇒ B

14. A potential difference of 10 V is applied across a conductance of 2 S. The current in the conductor will be ;

(A) 20 A
(B) 5 A
(C) 0.2 A
(D) None of these

Answer ⇒ A

15. Ohm’s law is valid when the temperature of conductor is :

(A) very low
(B) very high
(C) varying
(D) constant

Answer ⇒ D

16. The emf of a car battery is about :

(A) 2.5 V
(B) 4.5 V
(C) 8.6 V
(D) 12 V

Answer ⇒ D

17. Emf is measured in :

(A) joule
(B) joule/coulomb
(C) joule-coulombs
(D) joule/coulomb/metre

Answer ⇒ B

18. 1 kilowatt hour is commonly known as:

(A) unit
(B) 1 faraday
(C) 1 curie
(D) None of these

Answer ⇒ A

19. How many joules are equal to 1 kWh ?

(A) 3.6.x 10⁴
(B) 3.6 x 10⁵
(C) 3.6 x 10⁶
(D) None of these

Answer ⇒ C

20. Two bulbs 25 W, 220 V and 100 W, 220 V are given. Which has higher resistance ?

(A) 25 W
(B) 100 W
(C) both bulbs have equal resistance
(D) resistance of bulbs can not be compared

Answer ⇒ A

21. 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

22. Potentiometer measures the potential difference more accurately than a voltmeter because :

(A) It has a wire of high resistance
(B) It has a wire of low resistance
(C) It does not draw current from external circuit
(D) It draws heavy current from external circuit

Answer ⇒ C

23. The sequence of colour bands of a carbon resistance of 47 kΩ will be :

(A) yellow, violet, red
(B) yellow, violet, orange
(C) violet, yellow, orange
(D) red, red, violet

Answer ⇒ B

24. The colour code for a resistance of 35 kΩ with 5% tolerance is :

(A) Orange, green, orange and gold
(B) Red, yellow, black and gold
(C) Orange, green, orange and silver
(D) Orange, green, red and gold

Answer ⇒ D

25. In the figure, shows a wheatstone bridge circuit. Its 2 Acurrent enters A, then what is the current in the arm BC ?

(A) 3/2 A
(B) 1/2 A
(C) 2/3 A
(D) None of these

Answer ⇒ A

26. The resistivity of a conductor depends upon its :

(A) length
(B) area of cross-section
(C) resistance
(D) None of these

Answer ⇒ D

27. Internal resistance of a cell does not depend upon :

(A) electrode separation
(B) electrode material
(C) electrolyte
(D) electrolyte area

Answer ⇒ D

28. For which of the following dependence of drit velocity V_d on electric field E is ohm’s law obeyed ?

(A) v_d = √E
(B) v_d ∝ E
(C) v_d = E²
(D) v_d = constant

Answer ⇒ B

29. The voltage (V) and current (I) graph for a conductor at three different temperature T₁, T₂ and T₃ are shown in the following figure. It follows:

(A) T₁ > T₂ > T₃
(B) T₁ = T₂ = T₃
(C) T₁ < T₂ < T₃
(D) T₁ = T₂ ≈ T₃

Answer ⇒ A

30. If eight identical cells, each having an e.m.f. of 6V are connected in parallel, then the e.m.f. of the combination is :

(A) 1 V
(B) 1/8 V
(C) 48 V
(D) 6 V

Answer ⇒ D

31. Which part of the curve shown in the fig. represents the negative resistance ?

(A) AB
(C) CD
(B) BC
(D) DE

Answer ⇒ C

Class 12th physics objective question in English

S.N	Physics Objective English Medium
1.	ELECTRIC CHARGES AND FIELDS
2.	LECTROSTATIC POTENTIAL AND CAPACITANCE
3.	CURRENT ELECTRICITY
4.	MOVING CHARGES AND MAGNETISM
5.	MAGNETISM AND MATTER
6.	ELECTROMAGNETIC INDUCTION
7.	ALTERNATING CURRENT
8.	ELECTROMAGNETIC WAVES
9.	RAY OPTICS AND OPTICAL INSTRUMENTS
10.	WAVE OPTICS
11.	DUAL NATURE OF MATTER AND RADIATION
12.	ATOMS
13.	NUCLEI
14.	SEMI CONDUCTOR ELECTRONICS
15.	COMMUNICATION SYSTEMS