Class 12th physics Objective Qustions in English 2020 VVI Point

Class 12^th physics Objective Qustions in English 2020 VVI Point

1. The unit for an electrical field is :

·         volt

·         Ampere

·         ohm

·         NC⁻¹

Ans: NC⁻¹

2. When a conductor is heated, its resistance :

·         Increases

·         decreases

·         remains constant

·         depends upon the nature of the conductor

Ans: Increases

3. The electrical potential at a point inside a charged spherical shell is :

·         Zero

·         Constant

·         Variable

·         Maximum

Ans: Zero

4. What is the SI unit of magnetic dipole moment :

·         Am²

·         Am

·         Am⁻²

·         None

Ans: Am²

5. Mention the S.I unit of a magnetic field :

·         gauss

·         Tesla

·         Weber

·         None

Ans: Tesla

6. Kirchoff loop rule is a direct consequence of low of conservation of :

·         Charge

·         Momentum

·         Angular Momentum

·         Energy

Ans: Energy

7. Lenz’s law is in accordance with the low of conservation of :

·         Momentum

·         Angular Momentum

·         Charge

·         Energy

Ans: Energy

8. Which of the Following can be Deflected by a magnetic field :

·         α – rays

·         β – rays

·         γ – rays

·         a & b Both

Ans: a & b Both

9. Name the electromagnetic radiation used for viewing objects through haze & fog :

·         Infrared

·         rays

·         x-rays

·         Microwaves None

Ans: Infrared

10. Which Colour of light gets deviated the most when sunlight passes through a prism :

·         Red

·         Yellow

·         Violet

·         Green

Ans: Violet

11. The radius of curvature of a mirror is 20 cm. What is its Focal length :

·         5 cm

·         10 cm

·         20 cm

·         None

Ans: 10 cm

12. Electron & Proton are moving at the same speed. Which we having more Wavelength.

·         Electron

·         Proton

·         Both Have Same

·         None Of This

Ans: Electron

13. Which series of H-atom spectrum lies in the ultra-violet region :

·         Balmer series

·         Lyman series

·         Pascher series

·         None of this

Ans: Lyman series

14. What is Called Ratio Of Potential difference & Current :

·         Resistance

·         Resistivity

·         Conduction

·         none

Ans: Resistance

15. Electric current is Scalar or Vector :

·         vector

·         scalar

·         neither vector & scalar

·         none

Ans: scalar

16. If a wire stretched by a force, its resistance :

·         Increases

·         decreases

·         remains constant

·         None

Ans: Increases

17. The unit of electrical current density is :

·         Am²

·         Am

·         Am⁻²

·         Am⁻¹

Ans: Am⁻²

18. As temperature increases the conductivity of a semiconductor :

·         Increases

·         decreases

·         remains constant

·         None

Ans: Increases

19. Potential gradient has unit :

·         vm

·         vm⁻¹

·         vm⁻²

·         vm²

Ans: vm⁻¹

20. The SI unit for impedance is :

·         ohm

·         Henry

·         Volt

·         Ampere

Ans: ohm

21. The Caused of induced emf in a closed coil is :

·         Magnetic field

·         Magnetic flux

·         Rotation of coil

·         Change in Magnetic flux

Ans: Magnetic flux

22. The absolute permeability of free space in S.I units is :

·         1⁄4π×₁₀⁻⁷

·         ₁₀⁻⁷

·         4π×₁₀⁻⁷

·         4π×₁₀⁷

Ans: 4π×₁₀⁻⁷

23. Which part of the electromagnetic spectrum is used in a radar system?

·         Ultraviolet

·         infrared

·         Radio waves

·         x rays

Ans: Radio waves

24. Critical Angle (C) and refractive index (µ) of medium are related as :

·         µ = sin c

·         µ = cos c

·         µ = tan c

·         µ = cosec c

Ans: µ = cosec c

25. MeV is the unit for :

·         Voltage

·         Current

·         Power

·         Energy

Ans: Energy

26. Farad is unit for :

·         Electric current

·         electric potential

·         Energy

·         capacitance

Ans: capacitance

27. A positively charged body has :

·         excess of electron

·         deficit of electrons

·         excess of proton

·         deficit of proton

Ans: excess of proton

28. As a temperature rises, the resistance of a conductor :

·         Increases

·         decreases

·         remains constant

·         depends upon the nature of the conductor

Ans: Increases

29. Zener diode is used for :

·         Oscillations

·         amplifications

·         rectification

·         voltage stabilization.

Ans: voltage stabilization

30. eV is a unit for :

·         potential difference

·         power

·         energy

·         momentum

Ans: energy