Physics 11th Chap 11 : Topic 6 - Maryam Publications

Physics Chapter 11 : Topic 6

Electromotive Force (e.m.f.)

1 / 35

The electromotive force $\mathbf{e.m.f.}$ of a source is defined as:

A) Resistance offered by a battery

B) Force acting on electrons inside a conductor

C) Current produced by a battery

D) Energy supplied per unit charge by a source

2 / 35

The mathematical expression for $\mathbf{e.m.f.}$ is:

A) $\mathbf{E = IR}$

B) $\mathbf{E = QW}$

C) $\mathbf{E =}$ $\frac{\mathbf{Q}}{\mathbf{W}}$

D) $\mathbf{E =}$ $\frac{\mathbf{W}}{\mathbf{Q}}$

3 / 35

The SI unit of electromotive force is:

A) Ampere

B) Volt

C) Coulomb

D) Joule

4 / 35

A battery has an $\mathbf{e.m.f.}$ of $\mathbf{12\ V}$. This means that the battery:

A) Has $\mathbf{12\ \Omega}$ resistance

B) Transfers $\mathbf{12\ J}$ of energy to each coulomb of charge

C) Produces $\mathbf{12\ A}$ current in every circuit

D) Supplies $\mathbf{12\ C\ }$of charge every second

5 / 35

A source transfers $\mathbf{100\ J}$ of energy to move $\mathbf{20\ C}$ of charge around a circuit. Its $\mathbf{e.m.f.}$ is:

A) $\mathbf{2000\ V}$

B) $\mathbf{20\ V}$

C) $\mathbf{5\ V}$

D) $\mathbf{2\ V}$

6 / 35

The $\mathbf{e.m.f.}$ of a source is measured when:

A) Charge completes a full circuit through the source

B) Current becomes zero permanently

C) Resistance becomes infinite

D) Charge moves only through the external resistor

7 / 35

Which device converts chemical energy into electrical energy?

A) Battery

B) Heater

C) Motor

D) Resistor

8 / 35

A $\mathbf{1.5\ V}$ cell transfers $\mathbf{3\ J}$ of energy. The charge moved is:

A) $\mathbf{4.5\ C}$

B) $\mathbf{6\ C}$

C) $\mathbf{2\ C}$

D) $\mathbf{0.5\ C}$

9 / 35

The main difference between $\mathbf{e.m.f.}$ and potential difference is that:

A) $\mathbf{e.m.f.}$ exists only in resistors.

B) $\mathbf{e.m.f.}$ is energy supplied by source per charge, while potential difference is energy used per charge.

C) $\mathbf{e.m.f.}$ is measured only in amperes.

D) potential difference cannot be measured.

10 / 35

A source with greater $\mathbf{e.m.f.}$ can:

A) Eliminate resistance in the circuit

B) Always produce greater current

C) Supply more energy per coulomb of charge

D) Have zero internal resistance

11 / 35

A battery has an $\mathbf{e.m.f.\ }$of $\mathbf{9\ V}$. The energy supplied to $\mathbf{4\ C}$ of charge is:

A) $\mathbf{45\ J}$

B) $\mathbf{2.25\ J}$

C) $\mathbf{36\ J}$

D) $\mathbf{9\ J}$

12 / 35

A cell does not actually produce charge. Instead, it:

A) Stops charge flow

B) Removes all resistance

C) Creates electrons from nothing

D) Provides energy to move existing charges

13 / 35

The symbol commonly used for electromotive force is:

A) $\mathbf{V}$

B) $\mathbf{I}$

C) $\mathbf{R}$

D) $\mathbf{E}$ or $\mathbf{\varepsilon}$

14 / 35

If the energy supplied by a source doubles while charge remains constant, its $\mathbf{e.m.f.}$ will:

A) Remain unchanged

B) Double

C) Become half

D) Become zero

15 / 35

If the charge moved through a source doubles while energy supplied remains constant, the $\mathbf{e.m.f.}$ becomes:

A) Unchanged

B) Four times

C) Half

D) Double

16 / 35

A source with $\mathbf{e.m.f.\ \ 2\ V}$ transfers energy to charge in such a way that:

A) $\mathbf{2\ J}$ is supplied to every coulomb.

B) $\mathbf{2\ A}$ flows automatically.

C) $\mathbf{2\ C}$ is supplied to every joule.

D) Resistance becomes $\mathbf{2\ \Omega}$.

17 / 35

Which statement about $\mathbf{e.m.f.}$ is correct?

A) It depends only on external resistance.

B) It is the force that pushes electrons physically.

C) It is measured in watts.

D) It is the energy supplied per unit charge by a source.

18 / 35

A battery supplies $\mathbf{240\ J}$ of energy while moving $\mathbf{30\ C}$ of charge. Its $\mathbf{e.m.f.}$ is:

A) $\mathbf{6\ V}$

B) $\mathbf{4\ V}$

C) $\mathbf{8\ V}$

D) $\mathbf{10\ V}$

19 / 35

The work done by a source in moving charge around a complete circuit is related to:

A) Current only

B) $\mathbf{e.m.f.}$ and charge

C) Resistance only

D) Wire length only

20 / 35

A battery rated at $\mathbf{6\ V}$ compared with a battery rated at $\mathbf{3\ V}$ provides:

A) No energy per coulomb

B) Half the energy per coulomb

C) Same energy per coulomb

D) Twice the energy per coulomb

21 / 35

The $\mathbf{e.m.f.}$ of a cell is independent of:

A) Energy supplied per charge

B) Type of cell

C) Chemical reactions inside the cell

D) Amount of charge moved

22 / 35

When a battery is connected to a circuit, its role is to:

A) Increase resistance

B) Stop charge movement

C) Consume electrical energy

D) Transfer energy to charges

23 / 35

A source transfers $\mathbf{50\ J}$ energy to $\mathbf{10\ C}$ charge. The potential generated by the source is:

A) $\mathbf{0.2\ V}$

B) $\mathbf{5\ V}$

C) $\mathbf{500\ V}$

D) $\mathbf{10\ V}$

24 / 35

A voltmeter connected across an ideal cell measures its:

A) Resistance

B) Current capacity

C) $\mathbf{e.m.f.}$

D) Charge stored

25 / 35

The term “electromotive force” is misleading because:

A) It only applies to motors.

B) It does not involve energy.

C) It is not actually a mechanical force.

D) It is not measured in volts.

26 / 35

If a source moves $\mathbf{50\ C}$ charge and supplies $\mathbf{150\ J}$ energy, its $\mathbf{e.m.f.}$ is:

A) $\mathbf{0.3\ V}$

B) $\mathbf{7500\ V}$

C) $\mathbf{50\ V}$

D) $\mathbf{3\ V}$

27 / 35

Which situation represents a source with high $\mathbf{e.m.f.}$?

A) A source providing small energy per coulomb

B) A resistor with high resistance

C) A wire with large diameter

D) A source providing large energy per coulomb

28 / 35

The energy transferred by a source depends on:

A) Current and area only

B) Temperature only

C) $\mathbf{e.m.f.}$ and charge moved

D) Resistance and length only

29 / 35

A $\mathbf{12\ V}$ battery moves $\mathbf{5\ C}$ of charge. The energy supplied is:

A) $\mathbf{144\ J}$

B) $\mathbf{17\ J}$

C) $\mathbf{2.4\ J}$

D) $\mathbf{60\ J}$

30 / 35

The correct interpretation of a $\mathbf{1\ V}$ source is:

A) It has $\mathbf{1\ ohm}$ resistance.

B) It contains $\mathbf{1}$ coulomb charge.

C) It supplies $\mathbf{1}$ ampere current.

D) It transfers $\mathbf{1}$ joule energy per coulomb charge.

31 / 35

A cell’s $\mathbf{e.m.f.}$ is measured in an open circuit because:

A) No current flows, so terminal voltage equals $\mathbf{e.m.f}$.

B) Charge stops existing.

C) No energy exists inside the cell.

D) Resistance becomes zero.

32 / 35

If the $\mathbf{e.m.f.}$ of a source is increased, each coulomb of charge receives:

A) More energy

B) The same energy always

C) Less energy

D) No energy

33 / 35

The formula $\left( \mathbf{E =}\frac{\mathbf{W}}{\mathbf{Q}} \right)$ indicates that $\mathbf{e.m.f.}$ is a measure of:

A) Current produced

B) Resistance of the source

C) Charge flow rate

D) Energy transfer efficiency per charge

34 / 35

A source with zero $\mathbf{e.m.f.}$ would:

A) Transfer no energy per unit charge

B) Have infinite voltage

C) Supply energy to charges

D) Produce infinite current

35 / 35

The complete circuit requirement in the definition of $\mathbf{e.m.f.}$ emphasizes that:

A) Current must always be infinite.

B) Charge must return to the source after moving through the circuit.

C) Resistance must be zero.

D) Voltage cannot exist.

Your score is

0%