The unit of power is MCQ with Answer and Explanation

The unit of power is
A. Newton
B. Pascal
C. Watt
D. Joule
Answer: Option C
Solution (By JKSSB Mock Tests)
Watt (W) = Joule/second. SI unit of power. Horsepower is another unit (1 HP ≈ 746 W). Joule is energy, Newton force, Pascal pressure.

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Practice More Physics Questions

Question #1
According to Wien's Displacement Law, if the absolute temperature of a radiating black body is doubled, the wavelength corresponding to maximum spectral emissive power will:
A. Halve
B. Double
C. Remain unchanged
D. Increase four times

Correct Answer: Option A


Explanation:
Wien's Displacement Law states that the wavelength at which a black body emits maximum radiation (lambda_m) is inversely proportional to its absolute temperature (T). lambda_m * T = b (Wien's constant). If the temperature T is doubled (2T), the peak wavelength lambda_m must strictly halve to maintain the constant product.

This question belongs to: Science Physics
Question #2
The dimensional formula of surface tension is
A. [MT⁻²]
B. [ML⁻¹T⁻²]
C. [ML⁰T⁻²]
D. [MLT⁻²]

Correct Answer: Option A


Explanation:
Surface tension = force/length. Force dimensions [MLT⁻²], length [L], so [MLT⁻²]/[L] = [MT⁻²]. Also energy per area gives same dimensions: [ML²T⁻²]/[L²] = [MT⁻²].

This question belongs to: Science Physics
Question #3
The speed of sound in air at 20°C is approximately
A. 330 m/s
B. 343 m/s
C. 300 m/s
D. 360 m/s

Correct Answer: Option B


Explanation:
At 0°C ≈ 331 m/s, increases with temperature. At 20°C ≈ 343 m/s.

This question belongs to: Science Physics