Advertisements
Advertisements
Question
An electric kettle is rated 2.5 kW, 250 V. Find the cost of running the kettle for two hours at Rs. 5.40 per unit.
Advertisements
Solution
Given ,
Power of kettle , P = 2.5 kW
Voltage , V = 250 V
Time, t = 2 h
As , Energy , E = P × t
= 2.5 × 2 = 5 kWh
Cost per unit of energy = Rs 5.40
Cost for 5 kWh of energy = 5.40 × 5 = Rs 27
RELATED QUESTIONS
Which of the following units could be used to measure electric charge?
(a) ampere
(b) joule
(c) volt
(d) coulomb
The atoms of copper contain electrons and the atoms of rubber also contain electrons. Then why does copper conduct electricity but rubber does not conduct electricity?
The p.d. across a 3 Ω resistor is 6 V. The current flowing in the resistor will be:
(a) `1/2A`
(b) 1 A
(c) 2 A
(d) 6 A
Which type of circuit, series or parallel, is preferred while connecting a large number of bulbs:
(b) for lighting inside the rooms of the hotel?
Ten bulbs are connected in a series circuit to a power supply line. Ten identical bulbs are connected in a parallel circuit to an identical power supply line.
(a) Which circuit would have the highest voltage across each bulb?
Draw a schematic diagram of an electric circuit consisting of a battery of two cells each of 1.5 V, 5 Ω, 10 Ω and 15 Ω resistors and a plug key, all connected in series.
What is international convention of colour coding in a cable?
An electric bulb is rated 250 W, 230 V.
- the energy consumed in one hour, and
- the time in which the bulb will consume 1.0 kWh energy when connected to 230 V mains.
State expression for Cells connected in series.
The number of electrons constituting a 1-coulomb charge is ______.
