Advertisements
Advertisements
प्रश्न
Rewrite the following statement by selecting the correct option:
1 A = ____________ mA.
विकल्प
102
10-2
103
10-3
Advertisements
उत्तर
1 A = `10^3` mA.
APPEARS IN
संबंधित प्रश्न
Why does the cord of an electric heater not glow while the heating element does?
Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.
Why is the tungsten used almost exclusively for filament of electric lamps?
An electric iron of resistance 20 ohms draws a current of 5 amperes. Calculate the heat produced in 30 seconds.
A resistance of 25 Ω is connected to a 12 V battery. Calculate the heat energy in joules generated per minute.
The current passing through a room heater has been halved. What will happen to the heat produced by it?
The heat produced by passing an electric current through a fixed resistor is proportional to the square of:
(a) magnitude of resistance of the resistor
(b) temperature of the resistor
(c) magnitude of current
(d) time for which current is passed
The current passing through an electric kettle has been doubled. The heat produced will become:
(a) half
(b) double
(c) four time
(d) one-fourth
If the current flowing through a fixed resistor is halved, the heat produced in it will become:
How does the wire in the filament of a light bulb behave differently to the other wires in the circuit when the current flows?
What property of the filament wire accounts for this difference?
Give a scientific reason.
Tungsten metal is used to make a solenoid type coil in an electric bulb.
Solve the following example.
Two tungsten bulbs of wattage 100 W and 60 W power work on 220 V potential difference. If they are connected in parallel, how much current will flow in the main conductor?
Name any six domestic appliances based on the heating effect of electric current.
Write two devices based on the heating effect of electric current.
Explain the importance/uses of fuse wire.
An electric iron consumes energy at the rate of 420 W when heating is at the maximum rate and 180 W when heating is at the minimum rate. The applied voltage is 220 V. What is the current in each case?
A fuse wire repeatedly gets burnt when used with a good heater. It is advised to use a fuse wire of:
The heating element of an electric iron is made up of:
An electric bulb is connected to a 220 V generator. The current is 0.50 A. What is the power of the bulb?
An electric kettle consumes 1 kW of electric power when operated at 220 V. A fuse wire of what rating must be used for it?
How does use of a fuse wire protect electrical appliances?
(a) Observe the diagram given below and state whether the bulb will glow or not when we switch on K.
(b) Is it safe to handle the bulb when the switch is OFF?
(c) Give a reason for your answer in (b).
An electric component used as a safety device is electric circuit is ______.
Unscramble the following words:
SFEU
Name two electric devices for each where
- heating effect of current is used and
- magnetic effect of current is used.
Paheli took a wire of length 10 cm. Boojho took a wire of 5 cm of the same material and thickness. Both of them connected the wires as shown in the circuit given in the following figure. The current flowing in both the circuits is the same.
- Will the heat produced in both cases be equal? Explain.
- Will the heat produced be the same if the wires taken by them are of equal lengths but of different thickness? Explain.
What is an electric fuse made up of?
Name a few appliances which work on the basis of the heating effect of current.
An electric fuse is a wire made up of a material having ______ melting point.
An electrochemical cell converts ______ energy into ______ energy.
A fuse is used in an electric circuit to stop high currents flowing through the circuit.
The electric fuse works on the Joule heating principle.
Explain why fuse wire is always connected in a series arrangement.
In a set up the students coated iron nails with zinc metal and noted that, iron nails coated with zinc prevents rusting. They also observed that zinc initially acts as a physical barrier, but an extra advantage of using zinc is that it continues to prevent rusting even if the layer of zinc is damaged. Name this process of rust prevention and give any two other methods to prevent rusting.
An electric kettle of 2 kW is used for 2h. Calculate the energy consumed in
- kilowatt hour and
- joules.
Write an expression for the amount of heat produced in a resistor when an electric current is passed through it stating the meanings of the symbols used.
The graph of voltage vs current for four different materials is shown below.
Which of these four materials would be used for making filament of bulb?
