PHYSICS YEAR10

A metal of length 15.01m is heated until its temperature rises by 60⁰C. If it’s new length is 15.05, calculate its linear expansivity

• 0.0004/k

• 0.00004/K

• 0.004/K

• 0.04/K

When water is heated between 0⁰C and 4⁰C, its density

• increases for a while and then decreases

• decreases for a while and then increases

• increases

• decreases

• remains constant

A metal bar 50cm long at 15⁰Cis heated to 85⁰C. If it expands by 0.088cm, determine its linear expansivity

• (a) 4.0×10^{-5  0C}

• ^{(b) 2.5×10-5  0C}

• ^{(c) 6.3×10-2  0C}

• ^{(d) 1.2×10-1  0C}

• ^{(e) none of the above}

1.     When heat is applied to one end of a metal rod, molecules at the other end begin to vibrate with greater amplitude than before because heat has been transferred by

• (a) radiation

• (b) convection

• (c) conduction

• (d) radiation

• (e) none of the above

1.     Which of the following phenomena explains the fact that a house whose roof is coated with white will be cooler in the hot season than one coated with black paint?

• (a) conduction

• (b) convection

• (c) refraction

• (d) radiation

• (e) none of the above

Which part of a vacuum flask prevents heat loss by radiation?

• (a) The cork

• (b) the vacuum

• (c) the silvered surfaces

• (d) the pad at the bottom

• (e) none of the above

1.     Charges are usually concentrated at places where the surface is ………….

• (a)  straight

• (b) sharply curved

• (c) oval in shape

• (d) rectangular

• (e) none of the above

1.     When a biro rubbed on dry silk cloth is moved very close to a piece of paper on dry table, the pen is found to pick up the paper. This is because

• (a) both the pen and the paper are magnetized

• (b) the pen is magnetized but the paper is not

• (c) the pen is charged while the paper is magnetized

• (d) both the pen and the paper are charged

• (e) none of the above

1.     In using a gold leaf electroscope to determine the nature of electric charge on a body, it is observed that when the charges on the body and electroscope are the same, the divergence of the leaves

• (a) decreases

• (b) increases

• (c) cannot say

• (d) remains unchanged

• (e) disappears

1.     Capacitor is a device that …………. charges

• (a) produces

• (b) emits

• (c) store

• (d) accelerate

• (e) none of the above