The horizontal component of the initial speed of a particle projected at 30° 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.

The length of an iron bar is 100cm at 20°C. At what temperature will its length increase by 0.01%? [Linear expansivity of iron = 1.2 x 10\(^{-5}\)°C]

Which of the following statements about magnetic lines of force is not correct? They

• A. pass through even non-magnetic materials
• B. run from the north pole to the south pole
• C. are in a state of tension and tend to be shorted
• D. intersect one another

An object is placed 35 cm away from a convex mirror with a focal length of magnitude 15 cm. What is the location of the image?

• A. 26.25 cm behind the mirror
• B. 10.5 cm behind the mirror
• C. 26.25 cm in front of the mirror
• D. 10.5 cm in front of the mirror

A boy drags a bag of rice along a smooth horizontal floor with a force of 2N applied at the angle of 60^o to the floor. The work done after a distance of 3m is

• A) 3 J
• B) 4 J
• C) 5 J
• D) 6 J

The accelerating potential in a cathode ray oscilloscope is 2.5 kV. Calculate the maximum speed of the accelerated electrons. [ e = 1.6 x 10\(^{-19}\) C; Me = 9.1 x 10\(^{-31}\) kg]

A piece of stone attached to one end pf string is whirled round in a horizontal circle. When the string is suddenly cut, the stone will

• A. move towards te centre of the circle
• B. stop moving immediately
• C. move along a circular path of smaller radius
• D. fly off in a direction tangential to the circular path

In an experiment to determine Young's Modulus for a wire, several loads are attached to the wire and the corresponding extension measured. The tensile stress in each case depends on the

• A. load and the extension
• B. load and the radius of the wire
• C. radius of the wire and the extension
• D. extension and the original length of the wire

A bullet is fired from a gun at 30\(^o\) to the horizontal. The bullet remains in flight for 25s before touching the ground. Calculating the velocity of projection. [g = 10ms\(^{-2}\)]

Which of the following may be used to explain a mirage? I. Layers of air near the road surface have varying refractive indices in hot weather II. Road surfaces sometimes becomes invisible in hot weather III. Light from the sky can be refracted upwards after coming close to the road surface.

• A. I and III only
• B. II and III only
• C. II only
• D. I, II and III