Draw the circuit symbol for the bell.

a) What does LDR stands for?

b) Draw its circuit symbol.

c) What happens to the resistance of an LDR when light is shone on it?

Redraw the circuit shown below by including a light-dependent resistor in place of the thermistor.

 Explain why the bell would be silent when the LDR is in darkness.

Explain why the bell would ring when light shines on the LDR.

An electric circuit is designed to carry a current of $10 \mathrm{A}$. What problem may arise if the current rises above this value?

An electric circuit is designed to carry a current of $10 \mathrm{A}$. Name two devices that could be fitted into the circuit to protect the circuit if the current becomes dangerously high.