EJU EJU Science: Physics - Waves and Electricity 2 — Questions and Answers
Question 1: Ohm's Law states that the current through a conductor is:
- Directly proportional to the voltage and inversely proportional to the resistance (Correct answer)
- Directly proportional to resistance and inversely proportional to voltage
- Equal to the product of voltage and resistance
- Independent of voltage
Correct answer: Directly proportional to the voltage and inversely proportional to the resistance
Ohm's Law: I = V/R, meaning current equals voltage divided by resistance.
Question 2: Two resistors of 4Ω and 6Ω are connected in series. What is the total resistance?
- 10Ω (Correct answer)
- 2.4Ω
- 24Ω
- 5Ω
Correct answer: 10Ω
For resistors in series, total resistance R_total = R1 + R2 = 4 + 6 = 10Ω.
Question 3: Two resistors of 4Ω and 6Ω are connected in parallel. What is the total resistance?
- 2.4Ω (Correct answer)
- 10Ω
- 24Ω
- 5Ω
Correct answer: 2.4Ω
For parallel resistors, 1/R = 1/4 + 1/6 = 5/12, so R = 12/5 = 2.4Ω.
Question 4: What is electric power (P) in terms of voltage (V) and current (I)?
- P = VI (Correct answer)
- P = V/I
- P = I/V
- P = V + I
Correct answer: P = VI
Electric power is calculated as P = VI, the product of voltage and current.
Question 5: In a DC circuit, what happens to the total current when an additional resistor is added in parallel?
- Total current increases because the equivalent resistance decreases (Correct answer)
- Total current decreases because more resistance is added
- Total current remains unchanged
- Total current becomes zero
Correct answer: Total current increases because the equivalent resistance decreases
Adding a parallel branch lowers total resistance, so by I = V/R, total current from the source increases.
Question 6: What is the SI unit of electric charge?
- Coulomb (C) (Correct answer)
- Ampere (A)
- Volt (V)
- Ohm (Ω)
Correct answer: Coulomb (C)
The Coulomb (C) is the SI unit of electric charge, where one Coulomb equals the charge carried by approximately 6.24 × 10^18 electrons.
EJU EJU Science: Physics - Waves and Electricity 2
Ohm's Law states that the current through a conductor is: