12.2 Problems
545
potentiometer are 150 and 120 cm. Calculate the internal resistance of the
cell (Fig. 12.16).
[University of London]
Fig. 12.16
12.32 A thin uniform wire 50 cm long and of 1 resistance is connected to the
terminals of an accumulator of emf 2.2 V and the internal resistance 0.1
(Fig. 12.17). If the terminals of another cell can be connected to two points
26 cm apart on the wire without altering the current in the wire, what is the
emf of the cell?
[Northern Universities of UK]
Fig. 12.17
12.33 In a Wheatstone bridge, four resistors P, Q, R and S are arranged as in
Fig. 12.18. Show that
(a) condition for null deflection in the galvanometer G is
P
Q
=
R
S
(b) if a non-zero current i g flows through the galvanometer then
i g
i
=
Q R − P S
G(Q + S) + (P + R)(G + Q + S)
545
potentiometer are 150 and 120 cm. Calculate the internal resistance of the
cell (Fig. 12.16).
[University of London]
Fig. 12.16
12.32 A thin uniform wire 50 cm long and of 1 resistance is connected to the
terminals of an accumulator of emf 2.2 V and the internal resistance 0.1
(Fig. 12.17). If the terminals of another cell can be connected to two points
26 cm apart on the wire without altering the current in the wire, what is the
emf of the cell?
[Northern Universities of UK]
Fig. 12.17
12.33 In a Wheatstone bridge, four resistors P, Q, R and S are arranged as in
Fig. 12.18. Show that
(a) condition for null deflection in the galvanometer G is
P
Q
=
R
S
(b) if a non-zero current i g flows through the galvanometer then
i g
i
=
Q R − P S
G(Q + S) + (P + R)(G + Q + S)