Question 21
The diagram below shows five bulbs connected in a circuit.
Which of the switches, S1, S2, S3 and S4, should be closed for all the bulbs
to light up?
A. S1 and S2 only
B. S1 and S3 only
C. S1, S2 and S4 only
D. S2, S3 and S4 only
S3
S4
S2
S1
Which of the switches, S1, S2, S3 and S4, should be closed for all the bulbs
to light up?
A. S1 and S2 only
B. S1 and S3 only
C. S1, S2 and S4 only
D. S2, S3 and S4 only
S3
S4
S2
S1