# JAC 12th Physics important Question with Answer

JAC 12th Physics important Questions with Answers pdf | Jac important question of physics class 12 | Jac 12th important question 2022 | Jac 12th physics notes | Jac class 12 physics notes | JAC 12th Objective Question.

## JAC 12th Physics important Question with Answer

1. What is the S.I unit of magnetic dipole moment:

• Am²
• Am
• Am⁻²
• None

2. Mention S.I unit of magnetic field:

• Gauss
• Tesla
• Weber
• None

3. Name the electromagnetic radiation used for viewing objects through haze and fog:

• Infrared rays
• X-rays
• Microwaves
• None

4. What is called ratio of potential difference & current :

• Resistance
• Resistivity
• Conduction
• None

5. Electric current is scalar or vector :

• vector
• scalar
• neither vector nor scalar
• none

6. Refractive index of a medium is √2 . What is the value of critical angle for it :

• 45°
• 60°
• 90°
• None

7. What is the main aim of Davisson – Germer Experiment :

• Experimental verification of de – Broglie wave.
• To establish the wave nature of electron.
• To verify the ions of photoelectric laws.
• None of these.
Answer: To establish the wave nature of electron.

8. Name a physical quantity whose dimensions are the same as those of Plank’s constant.

• Momentum
• Angular momentum
• Energy
• Force

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

• 1/4π × 10⁻⁷
• 10⁻⁷
• 4π × 10⁻⁷
• 4π × 10⁻⁷

10. If a wire is stretched by a force , its resistance :

• increased
• decreases
• remain constant
• None

11. The unit of Electric current density is :

• Am
• Am²
• Am⁻²
• Am⁻¹

12. As temperature increases the conductivity of a sermiconductor :

• increased
• decreases
• remain constant
• None

13. Potential gradient has unit :

• vm
• vm⁻¹
• vm⁻²
• vm²

14. The SI unit for Impcdance is :

• ohm
• Henry
• Volt
• Ampere

15. The cause of induced cmf in a closed coil is :

• magnetic field
• magnetic flux
• Rotation of Coil
• change in magnetic flux

16. Which part of electromagnetic spectrum is used in radar System ? :

• Ultraviolet
• infrared
• X-rays

17. Critical angle ( C ) and refractive index ( μ ) of medium are related as :

• μ = Sin c
• μ = cos c
• μ = tan c
• μ = cosec c

18. Me V is the unit for :

• Voltage
• Current
• Power
• Energy

19. Forbidden energy gap of a semiconductor is of the order of :

• 0.1 ev
• 1 ev
• 10 ev
• 5 ev

20. Farad is a unit for

• Electric current
• Electric potential
• Energy
• Capacitance

21. A positively charged body has :

• excess of electrons
• deficit of electrons
• excess of protons
• deficit of protons

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

• Increases
• decreases
• remains constand
• depends upon nature of conductor

23. Drift velocity of free electrons in a conductor does not depend upon its :

• temperature
• length
• Area of cross – section
• material

24. Electromagnetic waves can be deflected by :

• electric field only
• magnetic field only
• both electric & magnetic field
• none of these

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• 2. 