Solution:
(i) A ray of light incident at the lens’ optical centre O goes through the lens without deviating.
(ii) After refraction, a ray of light incident parallel to the primary axis of the lens passes through or appears to emanate from the second focus F2 (in a convex lens) (in a concave lens)
(iii) After refraction, a ray of light passing through the first focus F1 of a convex lens or directed towards the first focus F1 of a concave lens emerges parallel to the major axis.
and 
, internal resistance 
and 
, connected in parallel. The equivalent emf of the combination is- (A) 
(B) 
(C) 
(D) 
and 
are collinear, prove that 
and 
be three points such that area of a 
is 4 sq units, find the value of 
.
and 
is 35 sq units.
and 
are collinear.
and 
are collinear.
and 
are collinear.
and 