Chapter Exam

Chapter-7 Electricity — Online MCQ Test

Q: What is the SI unit of electric current?

Answer: B. Ampere — The SI unit of electric current is ampere (A). It measures the rate of flow of electric charge.

Q: Which device is used to measure electric current in a circuit?

Answer: B. Ammeter — An ammeter is connected in series to measure current flowing through a circuit.

Q: If the potential difference across a resistor is doubled while its resistance remains the same, the current will:

Answer: C. Double — From Ohm's law, I = V/R. If V doubles and R is constant, the current also doubles.

Q: A student increases the length of a wire but keeps its material and thickness the same. What happens to its resistance?

Answer: B. It increases — Resistance is directly proportional to the length of a wire. So, increasing length increases resistance.

Q: A bulb glows dimly in a circuit. Which of the following is the most likely reason, based on Ohm's law?

Answer: B. The current through the bulb is low — A dim bulb indicates less current through the filament. Lower current usually means lower brightness.

SCIENCE · Samacheer Kalvi 9th · Tamil Nadu State Board

Practice Chapter-7 Electricity with a free chapter-wise online MCQ test for Tamil Nadu State Board Samacheer Kalvi 9th SCIENCE. This chapter covers: Description Covers electric circuits Ohm's law resistance and electrical applications Keywords Current Resistance Circuit Ohms Law Electricity. AI-generated questions from basic to board-exam level, with instant results and explanations.

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Chapter-7 Electricity — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board Samacheer Kalvi 9th SCIENCE — Chapter-7 Electricity, with answers and explanations. These are sample questions; the exam has its own separate question set.

What is the SI unit of electric current?

A. Volt
B. Ampere ✓
C. Ohm
D. Watt

Answer: B. Ampere
The SI unit of electric current is ampere (A). It measures the rate of flow of electric charge.

Which device is used to measure electric current in a circuit?

A. Voltmeter
B. Ammeter ✓
C. Galvanometer
D. Resistor

Answer: B. Ammeter
An ammeter is connected in series to measure current flowing through a circuit.

If the potential difference across a resistor is doubled while its resistance remains the same, the current will:

A. Become half
B. Remain the same
C. Double ✓
D. Become four times

Answer: C. Double
From Ohm's law, I = V/R. If V doubles and R is constant, the current also doubles.

A student increases the length of a wire but keeps its material and thickness the same. What happens to its resistance?

A. It decreases
B. It increases ✓
C. It becomes zero
D. It remains unchanged

Answer: B. It increases
Resistance is directly proportional to the length of a wire. So, increasing length increases resistance.

A bulb glows dimly in a circuit. Which of the following is the most likely reason, based on Ohm's law?

A. The circuit has no resistance
B. The current through the bulb is low ✓
C. The voltage is infinite
D. The switch is always off

Answer: B. The current through the bulb is low
A dim bulb indicates less current through the filament. Lower current usually means lower brightness.