Download App

Electricity — Science STD 10 — Question

CBSE BoardEnglish MediumSTD 10ScienceElectricity3 Marks
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

In an experiment to study the relation between the potential difference across a resistor and the current through it, a student recorded the following observations:

  
Potential Difference V(volts)
Current I(amperes)
1.0
0.1
2.2
0.2
3.0
0.6
4.0
0.4
6.4
0.6

On examine the above observations, the teacher asked the student to reject one set of readings as the values were out of agreement with the rest. Which one of the above sets of

readings can be rejected? Calculate the mean value of resistance of the resistor based on the remaining four sets of readings.

→
Describe an activity to show that the colours of white light splinted by a glass prism can be recombined to get white light by another identical glass prism. AIso draw ray diagram to show the recombination of the spectrum of white light.
→
What is the principle of an electric motor? Name some of the devices in which electric motors are used.
→
Draw the ray diagram and also state the position, relative size and nature of the image formed by a concave mirror when the object is placed between its centre of curvature, C and the focus, F.
→
Why should there be equitable distribution of resources? List three forces that would be working against an equitable distribution of our resources.
→
An object of size 7.0cm is placed at 27cm in front of a concave mirror of focal length 18cm. At what distance from the mirror should a screen be placed so that a sharp focussed image can be obtained? Find the size and nature of image.
[Hint. Find the value of image distance (v) first. The screen should be placed from the mirror at a distance equal to image distance.]
→
What would your image look like if you stood dose to a large:
  1. Convex mirror?
  2. Concave mirror?
Give reasons for your answer.
→
When is a person said to have developed cataract in his eye ? How is the vision of a person
having cataract restored?
→
What is the maximum number of 60W bulbs that can be run from the mains supply of 220 volts if you do not want to overload a 5A fuse?
→
a. Draw the pattern of magnetic field lines around a bar magnet. Mark the position of North Pole, South Pole and the places where the magnetic field is strongest.
b. Why do the magnetic field lines not intersect each other?
→