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51.

Fifteen bulbs, each labelled ' $200$ V $60$ W', are connected in parallel to a $200$ V supply. Which of the following fuses should be used in the circuit ?

52.

Circuit with D.C. source, fuse Y, fuse Z in series with a 21 ohm resistor, and fuse X in series with an 18 ohm resistor and switch K

In the circuit shown, $Y$ is a 5 A fuse, $Z$ and $X$ are 3 A fuses. When the switch $K$ is open the current passing through the $21\ \Omega$ resistor is $2.4$ A. When $K$ is closed, which of the fuses will be blown ?