Chapter Exam

Chapter 4: Electricity — Online MCQ Test

Q: What is the SI unit of electrical resistivity?

Answer: B. Ohm-meter — The SI unit of electrical resistivity (ρ) is ohm-meter (Ω m).

Q: According to Ohm's Law, if the temperature remains constant, the electric current (I) flowing through a conductor is directly proportional to what physical quantity?

Answer: C. Potential difference — Ohm's law states that electric current flowing through a conductor is directly proportional to the potential difference (V) across its ends at constant temperature.

Q: A charge of 120 Coulombs flows through an electric bulb in 2 minutes. What is the electric current flowing through the bulb?

Answer: A. 1 A — Electric current I = Q / t. Here Q = 120 C and time t = 2 minutes = 120 seconds. Therefore, I = 120 / 120 = 1 A.

Q: A cylindrical wire of length L and resistance R is stretched uniformly to double its original length (2L). What will be its new resistance?

Answer: C. 4R — When stretched to 2L, the area becomes A/2 (since volume is constant). New resistance R' = ρ(2L)/(A/2) = 4(ρL/A) = 4R.

Q: Three identical resistors, each of resistance R, are arranged such that two are in parallel and this set is in series with the third. If connected to a voltage source V, what is the total power dissipated in the circuit?

Answer: A. 2V² / (3R) — Parallel pair equivalent = R/2. Total resistance = R + R/2 = 1.5R = 3R/2. Total power P = V² / Req = V² / (3R/2) = 2V² / (3R).

SCIENCE · CLASS 10th · Tamil Nadu State Board

Practice Chapter 4: Electricity with a free chapter-wise online MCQ test for Tamil Nadu State Board CLASS 10th SCIENCE. This chapter covers: Focusing on electric current resistance and potential difference this chapter details Ohm Law series and parallel circuits. Students analyze Joule heating effect electrical power a.... AI-generated questions from basic to board-exam level, with instant results and explanations.

Questions

20m

Time Limit

Attempts Left

10 random questions from this chapter (mixed difficulty)
Questions you've seen before won't repeat until the pool resets
You have 20 minutes — exam auto-submits when time is up
Maximum 3 attempts per chapter
Results and explanations shown immediately after submission

New here? Register free — includes 3 free chapter exams.

Chapter 4: Electricity — Important Questions & Answers (FAQ)

Frequently asked questions from Tamil Nadu State Board CLASS 10th SCIENCE — Chapter 4: Electricity, with answers and explanations. These are sample questions; the exam has its own separate question set.

What is the SI unit of electrical resistivity?

A. Ohm
B. Ohm-meter ✓
C. Ohm / meter
D. Siemens

Answer: B. Ohm-meter
The SI unit of electrical resistivity (ρ) is ohm-meter (Ω m).

According to Ohm's Law, if the temperature remains constant, the electric current (I) flowing through a conductor is directly proportional to what physical quantity?

A. Resistance
B. Electric charge
C. Potential difference ✓
D. Electrical power

Answer: C. Potential difference
Ohm's law states that electric current flowing through a conductor is directly proportional to the potential difference (V) across its ends at constant temperature.

A charge of 120 Coulombs flows through an electric bulb in 2 minutes. What is the electric current flowing through the bulb?

A. 1 A ✓
B. 2 A
C. 60 A
D. 0.5 A

Answer: A. 1 A
Electric current I = Q / t. Here Q = 120 C and time t = 2 minutes = 120 seconds. Therefore, I = 120 / 120 = 1 A.

A cylindrical wire of length L and resistance R is stretched uniformly to double its original length (2L). What will be its new resistance?

A. 2R
B. R / 2
C. 4R ✓
D. R / 4

Answer: C. 4R
When stretched to 2L, the area becomes A/2 (since volume is constant). New resistance R' = ρ(2L)/(A/2) = 4(ρL/A) = 4R.

Three identical resistors, each of resistance R, are arranged such that two are in parallel and this set is in series with the third. If connected to a voltage source V, what is the total power dissipated in the circuit?

A. 2V² / (3R) ✓
B. 3V² / (2R)
C. V² / (3R)
D. 3V² / R

Answer: A. 2V² / (3R)
Parallel pair equivalent = R/2. Total resistance = R + R/2 = 1.5R = 3R/2. Total power P = V² / Req = V² / (3R/2) = 2V² / (3R).

← Previous Chapter

Chapter 3: Thermal Physics

Next Chapter →

Chapter 5: Acoustics