Which of the following instruments helps to maintain the correct humidity and temperature of a building?

• A. A compressor
• B. A refrigerator
• C. Air blower
• D. Air conditioner

Longitudinal waves cannot be

• A. diffracted
• B. retracted
• C. polarized
• D. reflected

A particle is dropped from a vertical height h and falls freely for a time t. With the aid of a sketch, explain how h varies with \(t^2\)

Which of the following waves requires a material medium for its propagation?

• A. Radio waves
• B. Light waves
• C. Sound waves
• D. X-rays

The cubic expansivity of a certain gas at constant pressure is \(\frac{1}{273} k^{-1}\). If a given mass of the gas is held at constant pressure and its volume at 0^oC is 273m³, determine the volume of the gas at 273^oC.

• A. 273m³
• B. 546m³
• C. 819³
• D. 1092³

Which of the following explains why a thick glass cup cracks when boiling water is poured into it?

• A. Unequal expansion of the exterior and interior walls of the cup
• B. Anomalous expansion of the water
• C. Greater specific latent capacity of water compared with that of glass
• D. Large increase in the heat capacity of the cup

A freshly demagnetized bar magnet is placed in the East-West direction to ensure that

• A. the molecular magnets remain randomly arranged.
• B. the molecular magnets are properly aligned
• C. it is affected by the earth's magnetic field
• D. the magnetic domains are within the earth's field

State three ways of increasing the rate of cooling of a cup of hot tea.

The equation of a certain progressive transverse wave is y = 2 sin 2 \(\pi ( \frac{t}{0.01} - \frac{x}{30})\), where x and y are in cm and t in seconds. Calculate the period of the wave.

• A. 0.001s
• B. 0.010s
• C. 10.000s
• D. 100.000s

When an object is placed between the principal focus and the optical center of a convex lens, it could be used as a?

• A) Simple microscope
• B) refecting lens
• C) compound microscope
• D) projector