GRADE 10 PHYSICS WEEK 2 REVIEW QUESTIONS

Which of the following is NOT a property of electric charge?

• A) Quantized

• B) Conserved

• C) Scalar

• D) Vector

Answer explanation

Electric charge is a fundamental property of matter that causes it to experience a force when near other electrically charged matter. It is a scalar quantity (meaning it has only magnitude, not direction) and exists in discrete amounts (quantized). Charge is also conserved, meaning the net charge in a closed system remains constant.

What is the SI unit of electric current?

• A) Volt

• B) Ampere

• C) Ohm

• D) Joule

What is the correct way to connect an ammeter in a circuit?

• A) In parallel

• B) In series

• C) Either in parallel or series

• D) Directly to the power source

Answer explanation

An ammeter is an instrument used to measure electric current in a circuit. It must be connected in series with the circuit to accurately measure the current flowing through it. This is because, in series, the current remains the same throughout the circuit.

The potential difference between two points in a circuit is measured in:

• A) Ampere

• B) Ohm

• C) Volt

• D) Joule

Which of the following statements is true regarding emf?

• A) It is a force

• B) It is the energy per unit charge produced by a source

• C) It is the same as voltage drop across the source

• D) It is always negative

Answer explanation

Electromotive force (emf) is not a force, but rather the energy provided by a source (like a battery or generator) to move electric charges through a circuit. It is the energy per unit charge produced by a source, and it is measured in volts (V). The emf is different from the voltage drop across the source because it represents the maximum potential difference a source can provide, while the voltage drop depends on the actual load in the circuit.

Where should a voltmeter be connected in a circuit to measure the potential difference across a resistor?

• A) In series with the resistor

• B) In parallel with the resistor

• C) Directly to the power source

• D) It does not matter

Answer explanation

A voltmeter is an instrument used to measure the potential difference (voltage) between two points in a circuit. To accurately measure the voltage across a resistor, it should be connected in parallel with the resistor. This is because the potential difference across components connected in parallel is the same.

A short circuit occurs when:

• A) There is a break in the circuit

• B) The resistance in the circuit becomes very high

• C) The current bypasses a part of the circuit, creating a path with very low resistance

• D) The voltage across the circuit is too low

Answer explanation

A short circuit occurs when the current bypasses a part of the circuit, creating a path with very low resistance. This can happen due to faulty wiring or damaged components. Short circuits can cause excessive current flow, which can lead to overheating and fires.

An open circuit is characterized by:

• A) Zero resistance

• B) Infinite resistance

• C) Constant voltage

• D) Constant current

Answer explanation

An open circuit is a circuit where the path for the current flow is interrupted, causing an infinite resistance. This can happen due to a broken wire, a disconnected component, or a switch being turned off. In an open circuit, no current flows through it.

In a closed circuit:

• A) The current flows without any interruptions

• B) The circuit is disconnected from the power source

• C) The circuit is broken, and no current flows through it

• D) The resistance in the circuit is very high

Answer explanation

In a closed circuit, the path for current flow is complete and uninterrupted. This allows the current to flow from the power source, through the components, and back to the power source. A closed circuit is necessary for electrical devices to function properly.

Which of the following particles carries a negative electric charge?

• A) Proton

• B) Neutron

• C) Electron

• D) Positron