Which of the following statements about the mouth piece of a telephone is correct? It converts sound energy into

• A. acoustic energy
• B. mechanival energy
• C. electrical energy
• D. heat energy

The effective potential energy,E, of a lunar satellite of mass,m, moving in an. elliptical orbit around the moon of mass,m, is given by

E = \(\frac{K^{2}}{2m_{1}r^{2}} - \frac{Gm_{1}m_{2}}{r}\) whereris the distance of the satellite from the moo? andGis the universal gravitational constant of dimensions, M\(^{-1}\)L\(^{3}\)T\(^{2}\).

?etermine the dimensions of the angular momentum,K, of the satellite using dimensional analysis.

Find the cost of running a 60W lamp for 24 hours. If 1kW hr cost 5 naira

• A. 14.4 naira
• B. 12.5 naira
• C. 7.2 naira
• D. 2.0 naira

Two objects, C and D, accelerate from rest at uniform rates. B accelerates twice as much as Compared to C, D travels

• A. at the same distance as C.
• B. six times as far.
• C. two times as far.
• D. three times as far.

Which of the following statements-about electromagnetic waves is not correct?

• A. They carry energy as they travel through space
• B. They travel with the speed of light
• C. They are longitudinal
• D. The electric and magnetic fields are at right angles to each other

A glass plate 0.9cm thick has a reflective index of 1.50. how long does it take for a pulse of light to pass through the plate? [c = 3.0 x 8 ms^-1]

• A) 4.5 x 10^-11s
• B) 4.5 x 10^-10s
• C) 4 .5 x 10^-12 s
• D) 3.0 x 10^-10s

(a) Explain what is meant by the statement: The capacitance of a parallel-plate capacitor is 2\(\mu\)F

(b) State: (i) three factors on which its capacitance depends

(ii) three uses of capacitors.

(c) Derive a formula for the energy W stored in a charged capacitor of capacitance C carrying a charge Q on either plate.,

(d) Two parallel-plate capacitors of capacitances 2\(\mu\)F and 3\(\mu\)F are connected in parallel and the combination is connected to a 50V d.c. source. Draw the circuit diagram of the arrangement and determine the:

(i) charge on either plate of each capacitor

(ii) potential difference across each capacitor

(iii) energy of the combinad capacitors.

When an alternating current given by I = 10sin (120π)t passes through a 12Ω resistor, the power dissipated in the resistor is

• A. 1200W
• B. 600W
• C. 120W
• D. 30W

The pitch of a musical note is determined by the frequency of the sound wave that it produces. If two instruments have the same frequency, which of the following factors will most affect the difference in their pitches?

• A. The shape of the instrument
• B. The tension of the string
• C. The size of the instrument
• D. The material of the instrument

Under which of the following conditions do gases conduct electricity?

• A) Low presssure and low p.d
• B) low pressure and high p.d
• C) high pressure an low p.d
• D) high pressure and high p.d