Case Study Questions for Class 10 Science Chapter 12 Electricity
Read the following and answer the questions from (i) to (v) given below:
The electrical energy consumed by an electrical appliance is given by the product of its power rating and the time for which it is used. The SI unit of electrical energy is Joule (as shown in figure).
Actually, Joule represents a very small quantity of energy and therefore it is inconvenient to use where a large quantity of energy is involved.
(i) The SI unit of electric energy per unit time is
(ii) Kilowatt-hour is equal to
(a) 3.6 ×104 J
(b) 3.6 ×106 J
(c) 36 ×106 J
(d) 36 ×104 J
(iii) The energy dissipated by the heater is E. When the time of operating the heater is doubled, the energy dissipated is
(c) remains same
(d) four times
(iv) The power of a lamp is 60 W. The energy consumed in 1 minute is
(a) 360 J
(b) 36 J
(c) 3600 J
(d) 3.6 J
(v) Calculate the energy transformed by a 5 A current flowing through a resistor of 2 Ω for 30 minutes.
(a) 40 kJ
(b) 60 kJ
(c) 10 kJ
(d) 90 kJ