Metal cables are used as telephone wires because

• A) they are cheap
• B) they are sourced locally
• C) the speed of sound in them is very low
• D) the speed of sound in them is very high

What is the speed of a particle of mass 10-27kg whose wavelength is 10-8m. [h = 6.63 x 10-34Js]

• A. 6.63ms-1
• B. 66.30ms-1
• C. 663.00ms-1
• D. 6630.00ms-1

Soft iron is used in making the armature of an electric bell because it

• A. retains its magnetism for a longtime
• B. Loses its magnetism readily
• C. Produces permanent magnets
• D. is not easily magnetised

Which of the following is TRUE of light and sound waves?

• A. they both transmit energy
• B. they both need a medium for propagation
• C. they are both transverse waves
• D. their velocities in air are equal

Which of the following assumptions is not valid for an ideal gas ?

• A. molecules of a particular gas are identical
• B. molecules moves freely throughout the volume of the container
• C. force of attraction between molecules is negligible
• D. molecules move at constant speed between collisions

An electric lamp marked 240v, 60 W is left to operate for an hour. How much energy is generated by the filament?

• A) 3.86 x 10⁵J
• B) 3.56 x 10⁵J
• C) 1.80 x 10⁴J
• D) 2.16 x 10⁵J

The process of energy production in the sun is

• A. nuclear fission
• B. nuclear fussion
• C. electron collision
• D. radioactive decay

Which of the following is/are characteristics of sound? I Pitch II. Loudness III. Quality IV Noise

• A. I only
• B. II only
• C. I and II only
• D. l, II and III only

The depolarising agent in a Leclanche cell is?

• A. carbon rod
• B. ammonium chloride
• C. manganese (IV) oxide
• D. zinc plate

A piece of metal is heated until it becomes red-hot, it is then quickly transferred into a beaker containing boiling water. What effect will this have on the boiling water?

• A. the boiling water rises slightly
• B. the boiling point rises sharply
• C. the rate of vaporisation of the boiling water increases
• D. the boiling point first rises and then falls