Online Test: Electricity | Class 10 Physics

Question 1 of 18

The SI unit of electric current is the:

volt

ampere

ohm

watt

Explanation: Current is measured in amperes (A).

Question 2 of 18

If 45 C of charge flows in 9 s, the current is:

$0.2\ \text{A}$

$5\ \text{A}$

$9\ \text{A}$

$45\ \text{A}$

Explanation: $I=\frac{Q}{t}=\frac{45}{9}=5\ \text{A}$.

Question 3 of 18

The potential difference is defined as work done per unit:

time

charge

current

resistance

Explanation: $V=\frac{W}{Q}$.

Question 4 of 18

Ohm's law is:

$V=\frac{I}{R}$

$V=IR$

$I=VR$

$R=VI$

Explanation: At constant temperature $V=IR$.

Question 5 of 18

A voltmeter is connected in a circuit:

in series

in parallel

with the key

after the fuse

Explanation: A voltmeter is always connected in parallel across the component.

Question 6 of 18

If $V=12\ \text{V}$ and $R=4\ \Omega$, the current is:

$3\ \text{A}$

$4\ \text{A}$

$8\ \text{A}$

$48\ \text{A}$

Explanation: $I=\frac{V}{R}=\frac{12}{4}=3\ \text{A}$.

Question 7 of 18

The resistance of a conductor is given by:

$R=\rho A l$

$R=\rho\frac{l}{A}$

$R=\frac{A}{\rho l}$

$R=\frac{\rho}{lA}$

Explanation: $R=\rho\frac{l}{A}$.

Question 8 of 18

The SI unit of resistivity is:

$\Omega$

$\Omega\ \text{m}$

$\Omega/\text{m}$

$\text{S}$

Explanation: Resistivity has units of ohm-metre ($\Omega\ \text{m}$).

Question 9 of 18

Three $6\ \Omega$ resistors in series give:

$2\ \Omega$

$6\ \Omega$

$12\ \Omega$

$18\ \Omega$

Explanation: $R_s=6+6+6=18\ \Omega$.

Question 10 of 18

Two $8\ \Omega$ resistors in parallel give:

$16\ \Omega$

$8\ \Omega$

$4\ \Omega$

$2\ \Omega$

Explanation: $\frac{1}{R_p}=\frac{1}{8}+\frac{1}{8}=\frac{1}{4}$, so $R_p=4\ \Omega$.

Question 11 of 18

In a series circuit, the quantity that stays the same through each resistor is:

voltage

current

power

resistance

Explanation: The same current flows through every series resistor.

Question 12 of 18

Household wiring uses which type of connection for appliances?

series

parallel

mixed only

short circuit

Explanation: Parallel wiring gives each appliance full voltage and independent control.

Question 13 of 18

Joule's law of heating states $H=$

$IRt$

$I^2Rt$

$VRt$

$\frac{V}{R}t$

Explanation: $H=I^2Rt$.

Question 14 of 18

Which is a correct expression for electric power?

$P=\frac{R}{V}$

$P=\frac{V^2}{R}$

$P=\frac{I}{R}$

$P=\frac{R}{I^2}$

Explanation: $P=VI=I^2R=\frac{V^2}{R}$.

Question 15 of 18

$1\ \text{kWh}$ in joules is:

$3.6\times10^{3}$

$3.6\times10^{6}$

$3600$

$10^{6}$

Explanation: $1\ \text{kWh}=1000\times3600=3.6\times10^{6}\ \text{J}$.

Question 16 of 18

A 220 V, 1100 W heater draws a current of:

$2\ \text{A}$

$5\ \text{A}$

$10\ \text{A}$

$22\ \text{A}$

Explanation: $I=\frac{P}{V}=\frac{1100}{220}=5\ \text{A}$.

Question 17 of 18

A bulb filament is made of tungsten because it has:

low melting point

high melting point

zero resistance

high resistivity only

Explanation: Tungsten's high melting point lets the filament glow without melting.

Question 18 of 18

An electric fuse protects a circuit by:

increasing current

melting and breaking the circuit on overload

storing charge

reducing voltage

Explanation: The low-melting fuse wire melts when current exceeds the safe limit.

Online Test — Electricity