Derive the expression for the heat produced due to a current ‘I’ … - Vidyadip

Question

Derive the expression for the heat produced due to a current ‘I’ flowing for a time interval ‘t’ through a resistor ‘R’ having a potential difference ‘V’ across its ends. With which name is this relation known?

✓

Answer

when an electric charge Q moves against a.p.d.V, the amount of work done is given by
W = Q × V .......(1)
We know, current, $\text{I}=\frac{\text{I}}{\text{T}}$
Q = I × t .....(2)
By ohm's law, $\frac{\text{V}}{\text{I}}=\text{R}$
V = I × R ........(3)
Putting eqs. (2) and (3) in eq (1),
W = I × t × I × R
W = I²RT
Assuming that all the electrical work done is converted into heat energy, we get Heat produced, H = I²Rt joules
This relation is known as Joule's law of heating,

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "Answer the questions.[Phy-3M]" from Electricity→Electricity — all question types→Science STD 10 question papers→CBSE Board STD 10 question papers→CBSE Board question paper generator→

Similar questions

Calculate the focal length of a convex lens which produces a virtual image at a distance of 50cm of an object placed 20cm in front of it.

To construct a ray diagram we use two rays of light which are so chosen that it is easy to determine their directions after reflection from the mirror. Choose these two rays and state the path of these rays after reflection from a concave mirror. Use these two rays to find the nature and position of the image of an object placed at a distance of 15cm from a concave mirror of focal length 10cm.

Draw a labelled diagram to show:

Reddish appearance of the sun at the sunrise or the sunset.
White appearance of the sun at noon when it is overhead.

Which of the following are concave mirrors and which convex mirrors?
Shaving mirrors, Car headlight mirror, Searchlight mirror, Driving mirror, Dentist’s inspection mirror, Torch mirror, Staircase mirror in a double-decker bus, Make-up mirror, Solar furnace mirror, Satellite TV dish, Shop security mirror.

Name the defect of vision which can be corrected by a diverging lens. Show clearly by a ray diagram how the lens corrects the defect.

Two coils A and B of insulated wire are kept close to each other. Coil A is connected to a galvanometer while coil B is connected to a battery through a key. What would happen if:

A current is passed through coil B by plugging the key?
He current is stopped by removing the plug from the key?

Explain your answer mentioning the name of the phenomenon involved.

A concave lens has a focal length of 20cm. At what distance from the lens a 5cm tall object be placed so that it forms an image at 15cm from the lens? Also calculate the size of the image formed.

Define principal axis, principal focus and focal length of a convex lens.

State what would happen to the direction of rotation of a motor if:

The current were reversed.
The magnetic field were reversed.
Both current and magnetic field were reversed simultaneously.

We wish to obtain an erect image of an object, using a concave mirror of focal length 15 cm. What should be the range of distance of the object from the mirror? What is the nature of the image? Is the image larger or smaller than the object? Draw a ray diagram to show the image formation in this case.