Which of the following statements about the mouth piece of a telephone is correct? It converts sound energy into

• A. acoustic energy
• B. mechanival energy
• C. electrical energy
• D. heat energy

The temperature of a liquid falls after some of it has evaporated because

• A. the liquid left is smaller in volume and the breeae easily cools it
• B. the more energetic molecules have escaped into the atmosphere
• C. the liquid left has less latent heat
• D. after evaporation impurites are left behind

Fusion is not usually used for generating electric power because

• A. no energy is released when fusion takes place
• B. very high temperatures are required to initiate fusion reaction
• C. the raw materials needed is not easily available
• D. heavy nuclei are involved

How long will it take to heat 3kg of water from 28^oC to 88^oC in an electric kettle taking 6a from a 220V supply? [specific heat capacity of water = 4180 J kg^-1K^-1]

• A. 120s
• B. 570s
• C. 600s
• D. 836s

Explain why water in a narrow glass tube has a concave meniscus while mecury in the same tube, has a convex meniscus

The velocity ratio of an inclined plane, inclines at an angle \(\theta\) to the horizontal can be expressed as

• A. (sin \(\theta)^{-1}\)
• B. \(\sin \theta\)
• C. (cos \(\theta)^{-1}\)
• D. \(\cos \theta\)

A particle is projected horizontally at 10 ms\(^{-1}\) from a height of 45m. Calculate the horizontal distance covered by the particle before hitting the ground. [g = 10ms\(^{-1}\)]

The sagging of overhead electrical cables is the consequence of

• A. linear expansivity
• B. . superficial expansivity
• C. cubic expansivity
• D. conductivity

A cell of e.m.f. 1.5V and internal resistance 1.0\(\Omega\) is connected to two resistor of resistance 2.0\(\Omega\) and 3.0\(\Omega\) in series. Calculate the current through the resistors

• A. 0.25A
• B. 0.30A
• C. 0.35A
• D. 0.50A

Which of the following quantities is a vector?

• A. speed
• B. distance
• C. energy
• D. momentum