State two advantages of an electromagnet over a permanent magnet. 

i) What will happen to a compass needle when the compass is placed below a wire and a current is made to flow through the wire? Give a reason to justify your answer.

A certain radioactive nucleus emits a particle that leaves its mass unchanged, but increases its atomic number by one. Identify the particle and write its symbol. 

i) Define the thermionic emission.

ii) Mention one use of thermionic emission.

State the properties that are common to and shown by both beta rays and cathode rays. 

PQ and PR are two light rays emerging from the object P as shown in the figure below:

i) What is the special name given to the angle of incidence (< PQN) of ray PQ?

ii) Copy the ray diagram and complete it to show the position of the image of the object P when seen obliquely from above.

iii) Name the phenomenon that occurs if the angle of incidence

A piece of iron of mass 2.0 kg has a thermal capacity of 966 J/^o C.

i) How much heat is needed to warm it by 15 degree C?

ii) What is it’s specific heat capacity in S.I. Units?

28.

In the figure below, the ammeter A reads 0.3 A. Calculate: 

i) the total resistance of the circuit.

ii) the value of R.

iii) the current flowing through r.