The SI unit of electric current is the ampere and the SI unit of electrical resistance is the ohm, so this CBSE Grade 10 sheet opens by fixing the two units behind V = IR. Ohm's law as V = IR and Joule's law as H = I²Rt also appear among the first answers.
Key Takeaways
The SI unit of electric current is the ampere (Q1).
The SI unit of electrical resistance is the ohm (Q2).
Q4 records Joule's law as H = I²Rt.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.What is the SI unit of electric current?
(a) volt(b) ampere(c) ohm(d) coulomb
2.What is the SI unit of electrical resistance?
(a) volt(b) ampere(c) ohm(d) watt
3.According to Ohm's law, the potential difference V across a conductor is
(a) V = IR(b) V = I ÷ R(c) V = R ÷ I(d) V = I + R
4.According to Joule's law of heating, the heat produced H in a resistor carrying current I for time t is
(a) H = I²Rt(b) H = IRt(c) H = I²R ÷ t(d) H = I²Rt²
5.In a series circuit containing resistors, the current
(a) is the same through each resistor(b) divides among the resistors(c) is different in every resistor(d) becomes zero
6.The commercial unit of electrical energy is
(a) joule(b) watt(c) kilowatt hour(d) volt
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.State Ohm's law and write its mathematical form.
8.Define resistance and state its SI unit.
9.What is the difference between a conductor and an insulator? Give one example of each.
10.State Joule's law of heating.
11.State two advantages of connecting electrical appliances in parallel in a house.
12.Define electric power and state its SI unit.
13.What is the commercial unit of electrical energy? Give its relation with the joule.
14.Why does the filament of a bulb glow brightly while the connecting wires remain almost cool?
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A current of 0.5 A flows through a conductor for 2 minutes. Find the quantity of charge that flows through the conductor. (Q = It)
16.A potential difference of 6 V is applied across a resistor of 3 Ω. Find the current flowing through it. (I = V ÷ R)
17.Two resistors of 4 Ω and 6 Ω are connected in series across a 20 V battery. Find the total resistance and the current in the circuit.
18.Three resistors, each of 2 Ω, are connected in parallel. Find the equivalent resistance of the combination. (1/R = 1/R₁ + 1/R₂ + 1/R₃)
19.An electric iron draws a current of 5 A from a 220 V supply. Find the power of the iron and the energy consumed in 2 hours. (P = VI, energy in kWh = power in kW × time in hours)
20.A heater of resistance 50 Ω is connected to a 220 V supply. Find the current drawn and the heat produced in 1 minute. (H = I²Rt, time in seconds)
Answer Key
1. b) ampere
2. c) ohm
3. a) V = IR
4. a) H = I²Rt
5. a) is the same through each resistor
6. c) kilowatt hour
7. Refer to solution guide.
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20. Refer to solution guide.
End of Worksheet
People Also Ask
What is the SI unit of electric current?
The ampere, option (b) in this worksheet (Q1).
What is the SI unit of electrical resistance?
The ohm, option (c) in this worksheet (Q2).
What is Joule's law of heating?
H = I²Rt, option (a) in this worksheet (Q4).
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