If the air inside a rigid box is heated, the i, average speed of the molecules increases ii. pressure of the air increases iii. average separation of the molecule increases. Which of the statements above are correct?

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

A man swung an object of mass 2 kg in a circular path with a rope 1.2 m long. If the object was swung at 120 rev/min, find the tension in the rope.

• A. 400
• B. 288
• C. 240
• D. 379

If a current of 2.5A flows through an electrolyte for 3 hours and 1.8g of a substance is deposited, what is the mass of the substance that will be deposited if a current of 4A flows through it for 4.8 hours?

• A. 2.4g
• B. 3.2g
• C. 4.6g
• D. 4.8g

The difference observed in solids, liquids and gases can be accounted for by

• A) The different molecules in each of them
• B) The spaces and forces acting between the molecules
• C) Thier melting points
• D) Their relative massess

The primary of a transformer has 100 turns and its secondary has 200 turns. If the voltage at the primary is 100V, determine the voltage at the secondary.

• A. 50V
• B. 100V
• C. 200V
• D. 400V

Which of the following is a percussion instrument?

• A. Flute
• B. Organ
• C. Bell
• D. Piano

A positively charged rod X is brought near an uncharged metal sphere Y and is then touched by a finger with X still in place. When the finger is removed, the result is that Y has

• A. no charge and a zero potential
• B. a positive charge and a zero potential
• C. a negative charge and a positive potential
• D. a negative charge and a negative potential

A current of 2A passes through a wire of resistance 4? for 3 minutes. Calculate the energy lost.

• A. 960J
• B. 1440J
• C. 2880J
• D. 48J

During the transformation of matter from the solid to the liquid state, the heat supplied does not produce temperature increase because

• A. all the heat is used to break the bonds holding the molecules of the solid together
• B. the heat capacity has become very large as the substance melts
• C. the heat energy is quickly conducted away
• D. the heat gained is equal to the heat lost by the substance

A blacksmith heated a metal whose cubic expansivity is 6.3 x 10^-6K^-1. The areal expansivity is

• A) 2.0 x 10-6K-1
• B) 2.1 x 10-6K-1
• C) 4.2 x 10-6K-1
• D) 6.3 x 10-6K-1