figure shows two long coaxial solenoids ,each of length L .The outer solenoid has an area of cross section A1 and number of turns / length n1 .The corresponding values for the inner solenoid are A2 and n2 .Write the expression for self inductance L1,L2 of the two coil and their mutual inductance M .Hence show that M

@ om prakash 

no image is attached with the ques. 
and your ques appears to be incomplete.

the expression for self inductance..

is 

NPHI=LI

WHERE L IS THE COEFFICIENT FOR SELF INDUCTANCE.

FOR SOLENOID=  L= u0n^2 A/L

where n is the no of turn per unit length 

a is the area , and u0 is the permeability.

MUTUAL INDUCTANCE OF SOLENOID 

M= u0N1N2A/L 

WHERE NI AND N2 ARE THE NO OF TURN IN SOLENOID 1 AND 2 RESPECTIVLY..

hope it helps 

cheers