lf the temperature of a small quantity of water in a closed container is gradually increased from 0° to 40°C then the density of the water within this range

• A. increases for a while and then decreases
• B. decreases for a while and then increases
• C. increases gradually
• D. decreases gradually

Electrical power is transmitted at a high voltage rather than low voltage because the amount of energy loss is reduced due to

• A. heat dissipation
• B. production of eddy currents
• C. excessive current discharge
• D. excessive voltage distance

The sound from a bell in an enclosed jar gradually faints away while the jar is being evacuated. Which of the following explains this observation?

• A. the pressue is reduced
• B. the sound waves are pumped out
• C. the waves are absorbed in the inner walls
• D. There is no more material medium

Which of the following statements correctly describe(s) cathode rays? i. they consist of tiny particles carrying negative electric charges. ii. they are deflected in a magnetic field but not in an electric field. iii. they consist of fast moving neutrons and deflected in an electric field.

• A. i only
• B. ii only
• C. i and ii only
• D. ii and iii only

Vapour is said to be saturated on top of an enclosed liquid if _________

• A. The rate of condensation is greater than that of vapourization
• B. The rate of condensation is equal to that of vapourization
• C. There is neither condensation nor vaporization of the liquid
• D. The rate of condensation is less that that of vaporization

A ray of light is incident on 'a plane mirror at an angle of 20°. This mirror is rotated through, twice this angle, In this new position the angle between the incident ray and the reflected ray is

• A. 20°
• B. 40°
• C. 80°
• D. 120°

An iron rod is moved from the earth to the moon. Which of the following properties of the rod would remain unchanged? i. mass ii. weight iii. relative density

• A. i only
• B. ii only
• C. iii only
• D. i and iii only

The motion of smoke particles from a chimney is typical of?

• A) random motion
• B) circular motion
• C) rotational motion
• D) oscillatory motion

A hose of cross-sectional area 0.5m2 is used to discharge water from a water tanker at a velocity of 60m/s in 20s into a container. If the container is filled completely, the volume of the container is

• A. 240m³
• B. 600m³
• C. 2400m³
• D. 6000m³

Which of the following can conduct electricity owing to the presence of free mobile electrons?

• A) germanium
• B) silicon
• C) grapefruit
• D) copper