Parallel Circuit

Which switches must be pressed to make bulb X come on?

• and 2 only

• and 3 only

• 2 and 3 only

• all three of them

Answer explanation

Closing switches 1 and 2 completes a circuit which includes bulb X

Parallel circuits are used for house lights:

• so they can all be switched on and off together.

• so you know when one breaks, because all the

  others go off.

• so they use a bigger current.

• so they can all be switched on and off

  separately.

Which of these statements is not true?

• The currents at Q and R add up to give the

  current at S.

• The current is the same at P and S.

• The current is the same at Q and R.

• The current is the same at P and Q.

Two identical lamps are connected in parallel. How bright are the lamps? 

• The top lamp is the brightest

• The lamps are the same brightness

• Both lamps are off

• The bottom lamp is the brightest

Answer explanation

The lamps have the same potential difference across them. The lamps are identical so they have the same resistance. The same amount of current flows through them. 

The lamps are the same brightness.

This is an example of a -------- circuit.

• Series

• Parallel

• Combination

This is an example of a -------- circuit.

• Series

• Parallel

• Combination

In this circuit, the bulb(s) that light up are:

• 1 only

• 2 only

• 1 and 2

• None of them

In this circuit, the bulb(s) that light up are:

• 1 only

• 2 only

• 1 and 2

• None of them

Tags

NGSS.MS-ETS1-1

The bulbs have the same resistance. The brightest bulb in this circuit is:

• 1 only

• 2 only

• Same brightness

• None of them

The bulbs have the same resistance. The brightest bulb is:

• 1 only

• 2 only

• 1 and 2

• None of them

Tags

NGSS.MS-PS3-5