Two mirrors of the same length are arranges as show in the diagram. A ray of light NO strikes the system at O and emerges along PQ. The emergent ray has been deviated through

• A. 220^o
• B. 200^o
• C. 210^o
• D. 180^o

The angle at which a projectile must be fired to cover maximum range is

• A. 30°
• B. 45°
• C. 60°
• D. 90°

blowing air over a liquid aids evaporation by

• A. increasing its surface area
• B. decreasing its vapour pressure
• C. increasing its temperature
• D. decreasing its density

A motorcycle starting from rest is uniformly accelerated such that its velocity in 10s is 72kmhr\(^{-1}\). What is its acceleration?

• A. 108ms\(^2\)
• B. 86ms\(^2\)
• C. 4ms\(^2\)
• D. 2ms\(^2\)

Given three capacitors 0.3μF, 0.5μF and 0.2μF, the joint capacitance when arranged to give minimum capacitance is

• A. 0.1μF
• B. 0.3μF
• C. 1.0μF
• D. 0.5μF

When viewed straight down, a fish in a pond is

• A. father below than it apperas to be
• B. mearer than it appears to be
• C. found at exactly the same point it is seen
• D. seen beside its image

(a) (i) Define atomic spectra.

(ii) Differentiate between emission spectra and absorption spectra.

(b)

The diagram below illustrates an electron transition from energy level n = 3 to n = 1. Calculate the:

(i) energy of the photon

(ii) frequency of the photon

(ii) wavelength of the photon [h = 6.6 x 10\(^{-34}\)J s, c = 3.0 x 10\(^8\) ms\(^{-1}\); 1 ev = 1.6 x 10\(^{-19}\) J]

c)(i)Differentiate between soft x-rays and hard x-rays

(ii) Draw the circuit symbol for a p-n junction diode.

(iiii) Give the reason for doping a semiconductor material

A copper cube weighs 0.25 N in air, 0.17N when completely immersed in paraffin oil and 0.15 N when completely immersed in water.The ratio of upthrust in oil to upthrust in water is

• A. 3 : 5
• B. 4 : 5
• C. 7 : 1
• D. 13 : 10

On a cold day, a concrete floor feels colder to the bear foot then a mat on the same floor because the

• A. is better conductor of heat than the foot
• B. mat loses heat to the bare foot at a faster rate
• C. mat is better conductor of heat than the floor
• D. concrete floor is a better conductor of heat than the mat

An object is dropped from the top of a tower. If it takes 4s for it to reach the ground, calculate the height of the tower.(g = 10 ms^-2, ignore air resistance)

• A. 20m
• B. 40m
• C. 80m
• D. 160m