Question Library

A coil of inductance 0.12 H and resistance 4\(\Omega\), is connected across a 240V, 50Hz supply. Calculate the current through it. [\(\pi\) = 3.142]

The work function of a metal is 2.56 x 10-19J. Calculate the frequency of a photon whose energy is required to eject from the metal an electron with kinetic energy of 3.0ev. [1 eV = 1.6 x 10-19J, h = 6.6 x 10-34Js]

The minimum energy required to cause photoelectric emission when the surface of a metal is irradiated with electromagnetic radiation of suitable frequency is called

Which of the following particles are termed nucleons in a neutral atom?

Which of the following statements about the use of radioisotopes is not correct? They are used to

An electric circuit is connected as illustrated above. Determine the equivalent e.m.f and current flowing through the circuit respectively, neglecting the internal resistance of the cells

Four co-planar forces of magnitudes 10N, 17N, 6N and 20N act at point O as shown in the above diagram. Determine the magnitude of the resultant force

The outlet of a bicycle pump is used to inflate a football as illustrated in the diagram above. Why does the pressure of the air inside the pump increases as the pump handle is slowly pushed downward at constant temperature?

The diagram above illustrates a waveform. Which of the point on the waveform are in phase?

You are provided with a constantan wire, a2 \(\Omega\)standard resistor, an accumulator E, an ammeter A, a key K, and other necessary apparatus. Measure and record the emf of the accumulator provided Connect a circuit as shown in the diagram above. Close the key, read and record the ammeter reading \(l_o\) when the crocodile clip is not in contact with the Constantan wire. Open the key with the clip making contact with the wire, when d=90cm, close the key. Read and record the ammeter reading l. Evaluate d\(^{_1}\) Repeat the procedure for four other values of d=80, 70, 60, and 50 cm In each case, read and record the ammeter reading and evaluatre d\(^{_1}\). Tabulate your readings. Plot a graph with I on the vertical axis and d\(^{_1}\) on the horizontal aXIS. Determine the slope, S of the graph and its intercept, c, on the vertical axis. Evaluate k = \(\frac{c}{s}\) Using your graph, determine the current I when d=55cm. State two precautions taken to obtain accurate results. (b)i. Explain what is meant by the potential difference between two points in an electric circuit. ii. State two factors on which the resistance of a wire depends.

A projectile is released with a speed u at an angle \(\theta\) to the horizontal. With the aid of a diagram, show that the time of flight is equal to \(\frac{2uSin\theta}{g}\), where g is the acceleration of free fall.

The horizontal component of the initial speed of a particle projected at 30^\circ to the horizontal is 50 ms\(^{-1}\). If the acceleration cf free fall due to gravity is 10ms\(^{-2}\), determine its: (a) initial speed; (b) speed at maximum height reached.

A mass of 11.0 kg is suspended from a rigid support by an aluminum wire of length 2.0 m, diameter 2.0 mm and Young's modulus 7.0 x 10\(^{11}\) Nm\(^{-2}\). Determine the extension produced. [g = 10 ms\(^{-2}\); \(\pi\) = 3.142]

(a) What is a polarizer? (b) With the aid of a diagram, explain how a polarizer can be used to polarize a beam of unpolarized light.

Name one use of 'LASER' in each of the following areas: (a) communication; (b) medicine; (c) security