physics

An electric cell with nominal voltage E has a resistance of 3Ω connected across it. If the voltage falls to 0.6E; the internal resistance of the cell is?

A. 1Ω B. 2Ω C. 3Ω D. 4Ω Correct Answer: Option C = 3Ω Explanation I = V/R = 0.6E/3 = 0.2E…

4 years ago

The electromagnetic wave that can produce a heating effect on the environment is?

A. x -rays B. ultraviolet rays C. infrared rays D. gamma rays Correct Answer: Option B - ultraviolet rays

4 years ago

An electric iron is rated 1000W; 230V. What is the resistance of its elements?

A. 51.9Ω B. 52.9Ω C. 55.9Ω D. 57.6Ω Correct Answer: Option B = 52.9Ω Explanation Electric Power = IV =…

4 years ago

The eye controls the amount of light reaching the retina by adjusting the?

A. cornea B. iris C. retina D. optic nerve Correct Answer: Option B - iris Explanation The iris controls the…

4 years ago

When connected to a mains of 250V; the fuse rating in the plug of an electric device of 1 KW is?

A. 2 A B. 3 A C. 4 A D. 5 A Correct Answer: Option C = 4 A Explanation…

4 years ago

The energy stored in a capacitor of capacitance 10μF carrying a charge of 100μC?

A. 5 x 104 J B. 4 x 102 J C. 4 x 10-3 J D. 5 x 10-4 J…

4 years ago

Vibration in a stretched spring cannot be polarized because they are?

A. stationary waves B. transverse waves C. longitudinal waves D. mechanical waves Correct Answer: Option C - longitudinal waves Explanation…

4 years ago

the pressure of 3 moles of an ideal gas at a temperature of 27°C having a volume of 10−³m³ is?

A. 2.49 x 105 Nm-2 B. 7.47 x 105 Nm-2 C. 2.49 x 106 Nm-2 D. 7.47 x 106 Nm-2 Correct Answer: Option D…

4 years ago

The phenomenon that makes sound persist when its source has been removed is known as?

A. acoustic vibration B. rarefaction C. echo D. reverberation Correct Answer: Option D - reverberation

4 years ago

Blowing air over a liquid aids evaporation by?

A. increasing its surface area B. decreasing its vapour pressure C. increasing its temperature D. decreasing its density Correct Answer:…

4 years ago