The external and internal diameter of a tube are measured as (32 ± 2)mm and (21 ± 1)mm respectively. Determine the percentage error in the thickness of the tube.

• A. 27%
• B. 14%
• C. 9%
• D. 3%

The accurate measurement of the relative density of a substance in its powdered form is done with a beam balance and?

• A. a density bottle
• B. an eureka can
• C. a pipette
• D. a burette

As the air column of length L in an air pipe decreases, the frequency of the sationary wave emitted

• A. decreases
• B. increases
• C. varies as L²
• D. varies as \(\sqrt{L}\)

A body is projected from the earth's surface with the intention of letting it escape from the earth's gravitational field. What is the minimum escape velocity of the body? [Earth's radius = 6.4 x 10³km, g = 10ms^-2]

• A. 14 kms^-1
• B. 13 kms^-1
• C. 12 kms^-1
• D. 11 kms^-1

The process of producing electric current by a changing magnetic field is referred to as

• A. magnet induction
• B. electromagnetic induction
• C. flux linkage
• D. electrostatic induction.

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

State three materials used for making optical fibres.

Which of the following devices does not makes use of eddy current for its action? A/An

• A. galvanometer
• B. speedometer
• C. induction furnace
• D. speedometer

One of the properties of gamma rays is that they are?

• A) neutral
• B) massive
• C) positively charged
• D) negatively charged

Calculate the temperature change when 500J of heat is supplied to 100g of water

• A. 12.1^oC
• B. 2.1^oC
• C. 1.2^oC
• D. 0.1^oC