Friday, 24 October 2014
Tuesday, 21 October 2014
Calculations on Resistance
1.
A motor has a resistance of 12 Ω. If the
supply voltage is 6 V calculate the current flowing through it.
I = V/R = 6/12 =
0.5A
2.
A current of 0.55 A flows through a
resistor of value 22 Ω. Calculate the voltage across the resistor.
A current of 0.55 A flows through a
resistor of value 22 Ω. Calculate the voltage across the resistor.
V = IR = 0.55 x 22 = 12.1V
3.
See
circuit diagram opposite. A bulb has a resistance of 9 Ω. The reading on the
ammeter is 0.17 A. Calculate the
reading on the voltmeter.
See
circuit diagram opposite. A bulb has a resistance of 9 Ω. The reading on the
ammeter is 0.17 A. Calculate the
reading on the voltmeter.
V = IR = 0.17 x 9 = 1.53V
4.
A motor has resistance of 210 Ω. A voltmeter placed in parallel with
the motor reads 5 V. calculate the current flowing through the motor.
I= V/R = 5/210 = 0.024A
5.
A power supply is set to 9V. Calculate the current flowing
through a 1.2 kΩ resistor.
1.2kΩ = 1200Ω Using I=V/R = 9/1200 =
0.0075A
6. A torch bulb is connected
to a 3V battery. It has a resistance of 8.5 Ω. Calculate the current flowing
through it.
I = V/R = 3/8.5 = 0.35A
7.
A light bulb is connected to a 240V supply. A current of 0.24
A flows throug it. Calculate the resistance of the bulb.
R=V/I = 240/0.24 = 1000Ω
8.
An electric drill is connected to a 240V supply. A current of
4 A flows through it. Calculate its resistance.
R=V/I = 240/4 = 60Ω
9.
The reading on the ammeter in the circuit opposite is 1.69 A.
The reading on the voltmeter is 10.9 V. Calculate the resistance of the bulb.
R=V/I = 10.9/1.69 = 6.5Ω
