Advertisements
Advertisements
Question
Who will spend more electrical energy? 500 W TV Set in 30 mins, or 600 W heater in 20 mins?
Advertisements
Solution
For T.V. set: Power = 500 W,
Time = 30 min = 30 × 60 s
∴ Energy = Power × time
E1 = 500 × 30 × 60 = 900 × 103 J
For Heater: Power = 600 W,
Time = 20 min = 20 × 60 s
∴ Energy (E2) = 600 × 20 × 60
= 720 × 103 J
Comparing E1 and E2, E1 > E2
∴ Energy spent by T.V. set (E1) is greater.
The energy consumed by the T.V. set is more than that consumed by the heater.
APPEARS IN
RELATED QUESTIONS
What do the following symbols mean in circuit diagrams?
What do the following symbols mean in circuit diagrams?
Draw circuit symbols for
fixed resistance
Draw circuit symbols for
a cell
Draw circuit symbols for
a battery of three cells
Explain the construction and working of the following. Draw a neat diagram and label it.
Electric motor
Distinguish between a closed circuit and an open circuit, with the use of suitable labelled diagrams.
Draw a neat diagram showing a closed electric circuit.
Explain the following:
Open circuit
What is open circuit?
Find the odd one out and give its explanation.
What is the use of earthing wire?
Study the three electric circuits below. Each of them has a glass rod (G), a steel rod (S), and a wooden rod (W).
In which of the electric circuits would the bulb not light up.
Which of the following a simple circuit must-have?
_____ has a thin metallic filament that melts and breaks the connection when the circuit is overheated.
What is electric circuit?
What is the role of the earth wire in domestic circuits?
Explain about domestic electric circuits. (circuit diagram not required)
A device that is used to break an electric circuit is called ______.
Instead of metal wires, a jute string can be used to make a circuit.
The rate of flow of electric charges in a circuit is called ______.
In a circuit, if the key is in open (off) condition, then electricity will not flow.
A child has drawn the electric circuit to study Ohm’s law as shown in Figure. His teacher told that the circuit diagram needs correction. Study the circuit diagram and redraw it after making all corrections.
In an electric circuit, the current starts from ______.
When an electric current flows through a copper wire AB as shown in the following figure, the wire
Three bulbs A, B, C are connected in a circuit as shown in the following figure. When the switch is ‘ON’
In an electric circuit a fuse is a ______ ______ to prevent possible fire.
The ______ is a species of fish that can give electric shocks of up to six hundred fifty watts of electricity.
Match the following
| 1. | Insulator | a. | Coulomb |
| 2. | Conductor | b. | Electric circuit |
| 3. | Closed path | c. | Copper |
| 4. | Electric charge | d. | Rubber |
In which of the following circuits A, B and C given in the following figure, the cell will be used up very rapidly?
Boojho has a cell and a single piece of connecting wire. Without cutting the wire in two, will he be able to make the bulb glow? Explain with the help of a circuit diagram.
Overloading of electric circuits can lead to short-circuiting.
A complete circuit is left on for several minutes, causing the connecting copper wire to become hot. As the temperature of the wire increases, the electrical resistance of the wire
An electric motor rated 1100 W is connected to 220 V mains. Find:
- The current drawn from the mains,
- Electric energy consumed if the motor is used for 5 hours daily for 6 days.
- Total cost of energy consumed if the rate of one unit is 5.
How is Joule's law effect useful in electric circuits where fuse is used as a safety device?
