Advertisements
Advertisements
Question
Name three main characteristics of an heating element.
Solution
The three main characteristics of an heating element are:
(i) It should have a high resistance so that a major amount of electric energy is converted into heat energy.
(ii) It should not get oxidised easily up to a temperature of 1000°C.
(iii) It should have a high melting point and a low thermal Expansion so that it does not get loosened on getting heated.
APPEARS IN
RELATED QUESTIONS
Define kilowatt-hour.
How many joules of electrical energy are transferred per second by a 6 V; 0.5 A lamp?
(a) 30 J/s
(b) 12 J/s
(c) 0.83 J/s
(d) 3 J/s
What is the current in the circuit shown (Fig. )
Name a metal that is used as an electron emitter. Give one reason for using this metal.
What is the resistance of an appliance rated at V volt, P watt?
An electrical appliance is rated 1500 W, 250 V. This appliance is connected to 250 V mains. Calculate:
(i) the current drawn,
(ii) the electrical energy consumed in 60 hours,
(iii) the cost of electrical energy consumed at Rs. 2.50 per kWh.
What is the commercial unit of electrical energy?
What is the commercial unit of electrical energy? Represent it in terms of joules.
A room has AC run for 5 hours a day at a voltage of 220V. The wiring of the room consists of Cu of 1 mm radius and a length of 10 m. Power consumption per day is 10 commercial units. What fraction of it goes in the joule heating in wires? What would happen if the wiring is made of aluminium of the same dimensions?
`[ρ_(Cu) = 1.7 xx 10_(Ωm)^-8, ρ_(Al) = 2.7 xx 10^-8 Ωm]`
