In the given figure, the Thevenin’s equivalent pair (voltage and impedance), as seen at the terminals P-Q, is given by
(a) 2 V, 5 Ω (b) 2 V, 7.5 Ω
(c) 4 V, 5 Ω (d) 4 V, 7.5 Ω
To find the Thevenin voltage open circuit the terminals P and Q.
By nodal analysis,
\frac{V_{ Th }-4}{10}+\frac{V_{ Th }}{10}=0 \Rightarrow 2 V_{ Th }-4=0 \Rightarrow V_{ Th }=2 V
To find the Thevenin resistance, short circuit the source.
R_{ Th }=\frac{10 \times 10}{10 \times 10}=5 \Omega
Linked Answer Questions 27 and 28: A coil of inductance 10 H and resistance 40 Ω is connected as shown in the figure. After the switch S has been in contact with point 1 for a very long time, it is moved to point 2 at t = 0.