The material of permanent magnet is MCQ with Answer and Explanation

The material of permanent magnet is
A. Steel
B. Aluminium
C. Soft iron
D. Copper
Answer: Option A
Solution (By JKSSB Mock Tests)
Steel has high retentivity, retains magnetism, used for permanent magnets. Soft iron has low retentivity, used for electromagnet core (temporary). Alnico, ferrites also used.

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Practice More Physics Questions

Question #1
Water boils at a lower temperature at high altitudes because
A. High humidity
B. Low density of air
C. Low atmospheric pressure
D. Low temperature

Correct Answer: Option C


Explanation:
Lower pressure reduces boiling point. Pressure cooker increases boiling point by raising pressure.

This question belongs to: Science Physics
Question #2
Which thermodynamic process occurs at a constant volume?
A. Adiabatic process
B. Isochoric process
C. Isobaric process
D. Isothermal process

Correct Answer: Option B


Explanation:
An isochoric process is a thermodynamic process in which the volume of the closed system remains constant (delta V = 0). Because there is no change in volume, the system does zero pressure-volume work (W = Pdelta V = 0). According to the first law of thermodynamics, any heat added goes entirely into increasing the internal energy. Isobaric is constant pressure; isothermal is constant temperature.

This question belongs to: Science Physics
Question #3
The velocity of a body changes from 2 m/s to 10 m/s in 4 s. Distance covered in this time is (assuming constant acceleration)
A. 24 m
B. 32 m
C. 48 m
D. 16 m

Correct Answer: Option A


Explanation:
a = (10-2)/4 = 2 m/s². s = 2×4 + ½×2×16 = 8+16=24 m. Or average velocity 6 m/s ×4=24.

This question belongs to: Science Physics