Fussing Of Bulb When It Is Switched On

A small bulb is placed at the focal point of a converging lens. When the bulb is switched on, the lens produces:

The given figure shows a simple circuit consisting of a bulb and a switch. On closing the switch, the bulb will

The given figure shows a simple circuit consisting of a bulb and a switch. On closing the switch, the bulb will

Zubeda made an electric circuit using a cell holder shown in Fig., a switch and a bulb. When she put the switch in the 'ON' position, the bulb did not glow. Help Zubeda in identifying the possible defects in the circuit.

The given figure shows a simple circuit containing four bulbs and five switches along with a battery. What is the minimum number of switches that must be closed to light at least one bulb?