For the circuit shown, which option is incorrect

Options

A. the potential at P is - 7.5 V
B. the potential at Q is - 1V
C. current in circuit is 1 amp.
D. the potential at S is zero

Answer

A

Explanation

The currnet in the circuit I=`((20-10))/((7.5+5+1+1))`=(10)/(10)`=1lamp
The potential difference across PS `V_(ps) = `7.5 xx 1` = 7.5 V
The potential difference across Q,R, `V_(QR)` = 1 x 1 = 1V
As point G is connected to earth hence potentials of S is zero.
The direction of the current in the circuit is from P to S, hence point P is at higher potential. `therefore`  `V_(p)` = 7.5 V
Similarly `V_(Q)` =-1 V