Electric power is P = V × I and the SI unit of electrical energy is the joule, so this Class 10 sheet begins with the power and energy equations for the home. The key records H = I² × R × t for heating and a fuse in a household circuit.
Key Takeaways
Electric power is P = V × I (Q1).
The SI unit of electrical energy is the joule (Q2).
The key records H = I² × R × t for heat.
Section A: Multiple Choice Questions (1 Mark Each)
Choose the correct option for each question.
1.Electric power in a circuit is given by
(a) P = V × I(b) P = V ÷ I(c) P = I ÷ V(d) P = V + I
2.The SI unit of electrical energy is
(a) joule(b) watt(c) volt(d) ampere
3.The heating effect of an electric current is given by Joule's law as
(a) H = I² × R × t(b) H = I × R × t(c) H = V ÷ (I × t)(d) H = I × t
4.Which safety device protects a circuit from overloading?
(a) a fuse(b) a switch(c) a wattmeter(d) an ammeter
5.In a household circuit, electric appliances are connected in
(a) parallel(b) series(c) either, it does not matter(d) a combination of only two appliances
6.In India, 1 unit of electrical energy consumed in homes equals
(a) 1 kWh(b) 1 watt(c) 1 joule(d) 1 volt
Section B: Short Answer Type Questions (2 Marks Each)
Show all steps clearly.
7.Write the formula for electric power in terms of voltage and current.
8.Define 1 watt.
9.State Joule's law of heating.
10.Why are household appliances connected in parallel?
11.What is the function of a fuse in a circuit?
12.What is the SI unit of electrical energy?
13.State two effects produced by an electric current.
14.Why is a fuse connected in series with the live wire?
Section C: Numericals & Word Problems (3 Marks Each)
Apply the concepts to solve the problems. Show all working.
15.A heater draws a current of 5 A at 220 V. Using P = V × I, find its power.
16.A bulb of power 60 W operates at 220 V. Using I = P ÷ V, find the current drawn.
17.A current of 2 A flows through a resistor of 10 Ω for 5 s. Using H = I² × R × t, find the heat produced.
18.A 1000 W appliance runs for 2 hours. Using energy = power × time, find the energy consumed in units (kWh).
19.A kettle of power 2000 W works at 220 V. Using R = V² ÷ P, find its resistance.
20.A room heater of 1500 W runs for 6 hours. Using energy = power × time, find the energy consumed in units, and if 1 unit costs ₹6, find the total cost.
Answer Key
1. a) P = V × I
2. a) joule
3. a) H = I² × R × t
4. a) a fuse
5. a) parallel
6. a) 1 kWh
7. Refer to solution guide.
8. Refer to solution guide.
9. Refer to solution guide.
10. Refer to solution guide.
11. Refer to solution guide.
12. Refer to solution guide.
13. Refer to solution guide.
14. Refer to solution guide.
15. Refer to solution guide.
16. Refer to solution guide.
17. Refer to solution guide.
18. Refer to solution guide.
19. Refer to solution guide.
20. Refer to solution guide.
End of Worksheet
People Also Ask
What is the formula for electric power?
P = V × I, option (a) in this worksheet (Q1).
What is the SI unit of electrical energy?
The joule, option (a) in this worksheet (Q2).
What device protects a household circuit?
A fuse, from the answer key on this page.
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