- Two correct rays from A and B to the screen intersecting at the pin hole;

- A real upright image shown on the screen;

Width of the aperture/ slit should be approximately or nearly equal to λ of the incident wave

b) No energy /power loss

Y;

Attracts more iron fillings since it forms a stronger magnet;

– Radioactivity is not affected by physical/ temperature /pressure changes while chemical reaction is affected by physical / temperature/pressure changes.

- Radioactivity is spontaneous while chemical reaction is not. Any correct difference

Bulb lights;

Zener diode conducts irrespective of biasing

a.c voltage can be stepped up or down by a transformer as opposed to a d.c voltages;

T= North

R= South

Protect appliance from damage in case excess current from the main

. Charge flowing through a conductor is slowed by collision with atoms and impurities in the conductor

- CRO measures both a.c and d.c voltages.

- CRO measures larger voltages without getting spoilt.

. White light is composed of seven colours;

Each colour, glass has a different value of n/λ or speed

. a) Short sight/ myopia;
b) Concave/ diverging lens;

a)

b) Rate of decay is a factor of atoms decaying or decay is exponential;

. a) Two correct rays from the object (head)to intersect forming the image of the head;

A real image drawn;

Height measured from student’s construction

a) The current flowing through a metal conductor is directly proportional to the pd across the ends of the metal provided that temperature and other physical conditions remains constant

a) X-rays penetrate paper, metal foils and body tissues but not light;

b) i) Through thermionic emission;

ii)

(I) λ increases;

(II) No effect /Remains the same;

iii) Better conductor of heat and hence conducts heat away faster to prevent heat from accumulating around the anode;

iv) has a higher melting point;

Hence withstands high heat energy without melting;

v) Reducing pd across the tube; which produces electrons moving relatively at lower velocities;