D.C. Circuits

Question 1

Single cell

Answer 1

Question 2

Lamp

Answer 2

Question 3

Battery of cells

Answer 3

Question 4

Variable Resister

Answer 4

Question 5

Thermister

Answer 5

Question 6

Light dependent resister (LDR)

Answer 6

Question 7

Ammeter

Answer 7

Question 8

Voltmeter

Answer 8

Question 9

Fuse

Answer 9

Question 10

Switch

Answer 10

Question 11

Diode

Answer 11

Question 12

Series circuit

Answer 12

Question 13

the current at every point in a series circuit is the_______________

Answer 13

same

Question 14

the sum of the potential differences in a series circuit is equal to the ______________

Answer 14

potential difference across the whole circuit also called EMF

Question 15

Current in parallel circuits

Answer 15

the current from the source is the sum of the currents in the separate branches of a parallel circuit.

Question 16

Answer 16

6 A

Question 17

Advantage of Parallel circuits

Answer 17

Question 18

When two resistors are connected in series, the potential difference across the power source is ______________

Answer 18

shared between them

Question 19

A _______________ is a single component that (in its simplest form) consists of a coil of wire with a sliding contact, midway along it

Answer 19

potentiometer

Question 20

In the fiure below, what happens as the slider is moved upward?

Answer 20

f the slider in the above diagram is moved upwards, the resistance of the lower part will increase and so the potential difference across it will also increase

Question 21

A relay consists of two parts

Answer 21

A coil (electromagnet)

A magnetic switch

Question 22

Answer 22

Question 23

A thermistor is a type of resistor (a thermal resistor) which changes its resistance when it is heated up:

As a thermistor gets hotter, its resistance _______

As it gets colder, its resistance __________

Answer 23

decreases, increases

Question 24

An LDR (Light Dependent Resistor) is a type of resistor which changes its resistance when light is shone on it. How does resistance change as light intensity varies?

Answer 24

When more light is shone on an LDR its resistance decreases

If an LDR is covered up (reducing the light hitting it) its resistance increases.

Question 25

Thermistors (or LDRs) may be used to create heat (or light) sensitive circuits, which perform certain actions when the temperature (or light) reaches a certain level

Answer 25

In the circuit below, an LDR is used, along with a relay, to control a bulb When it gets darker, the resistance of the LDR increases This causes the potential difference across the LDR to increase When this potential difference increases the current in the coil (part of the relay) will increase When the current gets large enough the coil will attract the switch, closing it and allowing a current to pass through the right-hand side of the circuit

Question 26

A diode is a component which only allows charge to flow in ______________ direction through it If a power source is connected back to front then there will be no current

Answer 26

one

Question 27

Rectification

Answer 27

If a diode is connected to an a.c. (alternating current) power supply, it will only allow a current half of the time.