Question
State and explain Joule’s law of heating.
✓
Answer
Joule's law of heating states that heat produced in joule when a current of I amphere flows in a wire of resistance R ohms for time t secounds is
Given by H = I2Rt
Thus the heat produced in a wire is directly proportional to:
Given by H = I2Rt
Thus the heat produced in a wire is directly proportional to:
- Square of current.
- Resistance of wire.
- Time for which current is passed.
Need a full question paper?
Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.
Explore more
Similar questions
Draw a labelled ray diagram to show how a ray of light passes through a parallel sided glass block:
- If it hits the glass block at 90° (that is, perpendicular to the glass block).
- If it hits the glass block at an angle other than 90° (that is, obliquely to the glass block).
If the length of a wire is halved and its cross-sectional area is doubled, then what would be the resistance of the wire? (Given, initially the resistance of the wire is R)
Which type of lens is:
- A converging lens, and which is.
- A diverging lens? Explain your answer with diagrams.
Draw the ray diagram and also state the position, the relative size and the nature of image formed by a concave mirror when the object is placed at the centre of curvature of the mirror.
A man standing in front of a special mirror finds his image having a very small head, a fat body and legs of normal size. What is the shape of:
- Top part of the mirror?
- Middle part of the mirror?
- Bottom part of the mirror?
An object is kept at a distance of 100cm from each of the above lenses. Calculate the (i) image distance and (ii) magnification in each of the two cases.
An object 20cm from a spherical mirror gives rise to a virtual image 15cm behind the mirror. Determine the magnification of the image and the type of mirror used.
What is the difference between regular reflection of light and diffuse reflection of light? What type of reflection of light takes place from:
- A cinema screen.
- A plane mirror.
- A cardboard.
- Still water surface of a lake
What possible values of resultant resistance one can get by combining two resistances, one of value 2 ohm and the other 6 ohm?