physics

A cell of internal resistance 2π supplies current to a 6π resistor. The efficiency of the cell is?

A. 12.0% B. 25.0% C. 33.3% D. 75.0% Correct Answer: Option C - 33.3% Explanation Internal resistance determines the maximum…

5 years ago

Calculate the specific latent heat of vaporization of steam of 1.13 x 106J of heat energy is required to convert 15kg of steam to water.

A. 7.53 x 105 Jkg−¹ B. 7.53 x 10-2 Jkg−¹ C. 7.53×104 Jkg−¹ D. 7.53 x 10-3 Jkg−¹ Correct Answer:…

5 years ago

Under which of the following conditions is workdone?

A. A man supports heavy food above his head with his hands B. A boy climbs onto a table C.…

5 years ago

Under what conditions are cathode rays produced in a discharge tube?

A. High pressure and low voltage B. High pressure and high voltage C. Low pressure and low voltage D. Low…

5 years ago

Calculate the upthrust on an object of volume 50cm³ which is immersed in a liquid of density 103kgm−³ [g = 10ms−²]

A. 0.8N B. 2.5N C. 0.5N D. 1.0N Correct Answer: Option C - 0.5N Explanation Upthrust = change in weight…

5 years ago

Why do soldiers march disorderly while crossing a bridge?

A. To prevent resonance on the bridge B. To set the bridge into resonance C. To make the bridge collapse…

5 years ago

Calculate the electric field intensity between two plates of potential difference 6.5V when separated by a distance of 35cm.

A. 18.57NC−¹ B. 53.06N C−¹ C. 2.28NC−¹ D. 0.80NC−¹ Correct Answer: Option A - 18.57NC−¹

5 years ago

The critical angle for light travelling from a transparent medium to air s measured as 34°. The refractive index of the medium is?

  A. 0.56 B. 1.50 C. 1.79 D. 2.02 Correct Answer: Option C - 1.79 Explanation N = 1/sinθ =…

5 years ago

A boy receives the echo of his clap reflected by a nearby hill 0.8s later. If the speed of sound in air is 3.40m/s; how far is he from the hill?

A. 66m B. 136m C. 264m D. 528m Correct Answer: Option B - 136m Explanation Distance = speed × time…

5 years ago

A solid weighs 45N and 15N respectively in air and water. Determine the relative density of the solid?

A. 0.33 B. 0.50 C. 1.50 D. 3.00 Correct Answer: Option D = 3.00 Explanation Weight in Air = 45N…

5 years ago