A simple microscope forms an image 10cm from an eye close to the lens. If the object is 6cm from the eye, calculate the focal length of the lens

• A. 3.75cm
• B. 4.00cm
• C. 15.00cm
• D. 16.00cm

(a) A particle moves on a straight path with an initial speed u and final speed v in time t. Show that the total distance X covered by the particle is given by

\(x = ut + \frac{1}{2}at^2\)

where a is the magnitude of acceleration

(b) State;

(i) Newton's second law of motion

(ii) the principle of conservation of energy

(iii) the law of floatation.

(c) Consider a balloon of mass 0.030 kg being inflated with a gas of density 0.54 kg m\(^{-3}\). What will be the volume of the balloon when it just begins to rise in air of density 1.29 kg m\(^{-3}\)? [ g = 10 ms\(^{-2}\)]

If the radius of the earth is 6.4 x 10⁶m, the escape velocity of a satellite from the earth is? [g = 10 ms^-2]

• A) 1.13 x 10⁴ ms^-1
• B) 9.00 x 10³ ms^-1
• C) 8.00 x 10³ ms^-1
• D) 1.27 x 10⁴ ms^-1

How long does it take a 750W heater to raise the temperature of 1kg of water from 20^oC to 50^oC [specific heat capacity of water = 4200Jkg^-1K^-1]

• A. 84s
• B. 112s
• C. 168s
• D. 280s

One common characteristics of solids, liquids and gasses is that?

• A. all the three has fixed volume
• B. their molecule have the same size
• C. their molecules are always in motion
• D. all the three have the same inter molecular forces

The sound from a vibrating tuning sound is when the tip of its stem is placed on a wooden table than when in air because

• A. the friction between the table and the tuning fork generates additional energy
• B. air molecules obsorb sound wave but wood transmit sound waves
• C. the table increases the frequency of the turning fork
• D. a large mass of air is set into vibration by the table

On a basis of the kinetic theory, an increase in the temperature of a fixed volume of an ideal gas causes

• A. a incease in the number of gas molecules
• B. a decrease in the density of the gass
• C. an increase in the average speed of the gas molecules
• D. a decrease in pressure exerted by the gas

Which of the following waves is not transverse

• A. light waves
• B. sound waves
• C. sea waves
• D. radio waves

A faulty barometer reads 72.6cm Hg when the atmospheric pressure is 75.0cm Hg. Calculate the atmospheric pressure when the barometer reads 72.0cn Hg

• A. 79.4cm Hg
• B. 74.38cm Hg
• C. 74.2cm Hg
• D. 69.4cm Hg

A luminous object is one that

• A. gives off dim blue-green light only in the dark.
• B. gives out light of its own
• C. shines by reflected light only
• D. glows only in the presence of light