Advertisements
Advertisements
Question
A heating coil has a resistance of 200 Ω. At what rate will heat be produced in it when a current of 2.5 A flows through it?
Advertisements
Solution
I = 2.5 A
R = 200 Ω
Rate of heat produced = Power = I2R = (2.5)2(200) = 1250 J/s
APPEARS IN
RELATED QUESTIONS
How does the resistance of a wire vary with its area of cross-section?
When current is switched ‘on’ in a room heater, it ______.
An electric room heater draws a current of 2.4 A from the 120 V supply line. What current will this room heater draw when connected to 240 V supply line?
Give two reasons why nichrome alloy is used for making the heating elements of electrical appliances.
If the current flowing through a fixed resistor is halved, the heat produced in it will become:
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 the factors on which the heat produced in a wire depends when current is passed in it, and state how does it depend on the factors stated by you.
In an electric bulb, coil of _______ metal is used.
Write scientific reason.
A coil made up of alloy Nichrome is used in the electric heater cooker as a resistor.
Name any two appliances which works on the phenomenon of heating effect of electric current.
When does overloading occur?
Explain the heating effect of electric current.
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:
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:
How does use of a fuse wire protect electrical appliances?
Why is parallel arrangement used in domestic wiring?
Can we use the same fuse in a geyser and a television set? Explain.
Two students decided to investigate the effect of water and air on iron object under identical experimental conditions. They measured the mass of each object before placing it partially immersed in 10 ml of water. After a few days, the object were removed, dried and their masses were measured. The table shows their results.
| Student | Object | Mass of Object before Rusting in g |
Mass of the coated object in g |
| A | Nail | 3.0 | 3.15 |
| B | Thin plate | 6.0 | 6.33 |
What might be the reason for the varied observations of the two students?
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.
