ANOTHER TEASER FROM HALF YEARLY PAPER

Qn. When the current sensitivity of a galvanometer increases, the voltage sensitivity
       (a)  increases     (b)  decreases     (c)  may or may not increase      (d)  does not change
My take:  (c) may or may not increase
Explanation:

Consider four cases: (i) N - no. of turns, (ii) B - magnetic induction through the coil, (iii) A - area of the coil (not cross-sectional area) and (iv)  c - couple per unit twist

Now,
C.S. = θ/I = NBA/c ==>

C.S can be increased by increasing (i) N, (ii) B or/and (iii) A. Also by (iv) decreasing or having low c value. Qn. does not say how C.S has been increased. 

It might be due to increase in B, say. 

In that case [as also in cases (iii) and (iv)], C.S. obviously will increase and so too will V.S.  [since V.S. = θ/V = θ/IG]. But when C.S is increased by increasing N, V.S. will not increase.

==> When C.S. increases, V.S. may increase [case (ii), (iii) and (iv)] or may not increase [case (i)].

Pl give your opinion.