A transformer has 400 primary turns and 100 secondary turns. If primary voltage is 220 V, secondary voltage is MCQ with Answer and Explanation

A transformer has 400 primary turns and 100 secondary turns. If primary voltage is 220 V, secondary voltage is
A. 55 V
B. 880 V
C. 110 V
D. 440 V
Answer: Option A
Solution (By JKSSB Mock Tests)
Vs/Vp = Ns/Np => Vs = 220 × (100/400) = 55 V. Step-down.

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If a stone dropped from the top of a tower reaches the ground in 4 seconds, what is the approximate height of the tower? (Take g = 10 m/s²)
A. 160 m
B. 40 m
C. 60 m
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Correct Answer: Option D


Explanation:
Using the second equation of motion for free fall: h = ut + ½gt². Since it is dropped, initial velocity (u) = 0. Time (t) = 4s, g = 10 m/s². The height h = 0 + ½(10)(4)² = 5 × 16 = 80 meters.

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D. Fat molecules

Correct Answer: Option B


Explanation:
Microwave ovens use electromagnetic radiation in the microwave frequency range (usually around 2.45 GHz). Water molecules have a permanent electric dipole moment. The oscillating electric field of the microwaves rapidly forces the water molecules to flip back and forth to align with the field, generating thermal energy via friction and effectively heating the food from within.

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Which scientific instrument is used specifically for measuring very high temperatures, such as the surface temperature of the Sun or inside a furnace, from a distance?
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Correct Answer: Option B


Explanation:
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