A battery lights up all the four lamps as shown in figure. When one of the lamp filament melts, the other three lamps stay on. Which of the following lamp filaments melt? 
(a) P
(b) Q
(c) R
(d) S
A battery lights up all the four lamps as shown in figure. When one of the lamp filament melts, the other three lamps stay on. Which of the following lamp filaments melt?
(a) P
(b) Q
(c) R
(d) S