A wire of resistance R is cut into three equal parts. These parts are then connected in parallel. The equivalent resistance is MCQ with Answer and Explanation

A wire of resistance R is cut into three equal parts. These parts are then connected in parallel. The equivalent resistance is

A. 3R

B. R/9

C. R/3

D. R

Answer: Option B

Each part resistance = R/3. Three such in parallel: 1/R_eq = 3/(R/3) = 9/R => R_eq = R/9. For n equal parts cut and connected parallel, R_eq = R/n².

This question belongs to: Science Physics

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Question #1 Report Error

The frequency of a wave is 1000 Hz. Its time period is

A. 1 s

B. 0.001 s

C. 0.01 s

D. 1000 s

Correct Answer: Option B

Explanation:
T = 1/f = 1/1000 = 0.001 s = 1 ms. Millisecond. For higher frequency, period shorter.

This question belongs to: Science Physics

Question #2 Report Error

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

A. 110 V

B. 440 V

C. 880 V

D. 55 V

Correct Answer: Option D

Explanation:
Vs/Vp = Ns/Np => Vs = 220 × (100/400) = 55 V. Step-down.

This question belongs to: Science Physics

Question #3 Report Error

The amount of heat required to raise temperature of 1 g water by 1°C is

A. 1 cal

B. 1 J

C. Both B and C

D. 4.2 J

Correct Answer: Option C

Explanation:
1 cal = 4.186 J ≈ 4.2 J. So both are correct. However option D covers both. I'll set D as correct.

This question belongs to: Science Physics