Advertisements
Advertisements
Question
In which of the following cases more electrical energy is consumed per hour?
(i) A current of 1 ampere passed through a resistance of 300 ohms.
(ii) A current of 2 amperes passed through a resistance of 100 ohms.
Advertisements
Solution
(i) I = 1 A
R = 300 Î
t = 1 h
Electrical energy consumed = `I^2xxRxxt`
= (1)2 (300) (1)
= 300 Wh
(ii) I = 2 A
R = 100 Î
Electrical energy consumed = `I^2xxRxxt=(2)^2(100)(1)=400Wh`
Thus, more electrical energy is consumed in case (ii).
APPEARS IN
RELATED QUESTIONS
Define the unit of current.
Draw the electrical symbols of the following components and state its use:
Ammeter.
What is the current in a circuit if the charge passing each point is 20 C in 40 s?
State the factors on which the strength of electric current flowing in a given conductor depends.
The rating of a fuse connected in the lighting circuit is ______.
If a charge of 420 C flows through a conducting wire in 5 minutes what is the value of the current?
Calculate the amount of energy transferred by a 10 A electric current flowing through a resistor of 5 o for 15 minutes.
What is international convention of colour coding in a cable?
A charge of 80 C flows in a conductor for 2 minutes.
(a) Calculate the current flowing through the conductor.
(b) If the current through a heater is 4 A what charge must be passing in 8 seconds?
An electric bulb is rated '100 W, 250 V'. How much current will the bulb draw if connected to a 250 V supply?
A bulb is connected to a battery of p.d. 4 V and internal resistance 2.5 Ω . A steady current of 0.5 A flows through the circuit. Calculate:
The total energy supplied by the battery in 10 minutes
Three resistances, of which two are equal when connected in series have an effective resistance of 30 ohms. When the three resistances are connected in parallel, the effective resistances is 3 ohms. Find the values of the individual resistances.
In current electricity, a positive charge refers to ______.
One unit of electrical energy consumed is equal to 1000 kilowatt-hour.
A current of 1 A is drawn by a filament of an electric bulb. Number of electrons passing through a cross section of the filament in 16 seconds would be roughly
Match the following:
| 1. | 1 mA | a. | series |
| 2. | 1 pA | b. | ohmmeter |
| 3. | Ammeter | c. | 10-6 ampere |
| 4. | Electrical resistivity | d. | 10-3 ampere |
Problems for practice:
If 3A current flows through a circuit, then convert the current in terms of a milliampere.
