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:
  1. Square of current.
  2. Resistance of wire.
  3. 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.

Start Generating Free

Similar questions

Describe with the help of a ray diagram the nature, size and position of the image formed when an object is placed in front of a convex lens between focus and optical centre. State three characteristics of the image formed.
When an object is placed 20cm from a concave mirror, a real image magnified three times is formed. Find:
  1. The focal length of the mirror.
  2. Where must the object be placed to give a virtual image three times the height of the object?
A converging lens of focal length 5cm is placed at a distance of 20cm from a screen. How far from the lens should an object be placed so as to form its real image on the screen?
When one enters a less lighted room from a place of intense light, he is not able to see anything for sometime, but after sometime the things become somewhat visible. Explain how this happens?
An erect image 2.0cm high is formed 12cm from a lens, the object being 0.5cm high. Find the focal length of the lens.
A combination of lenses for a camera contains two converging lenses of focal lengths 20cm and 40cm and a diverging lens of focal length 50cm. Find the power and focal length of the combination.
What is an ammeter? How is it connected in a circuit? Draw a diagram to illustrate your answer.
You are given one hundred $1 Ω $ resister. What is the smallest and largest resistance you can make in a circuit using these?
  1. Draw a diagram to show how a converging lens focusses parallel rays of light?
  2. How would you alter the above diagram to show how a converging lens can produce a beam of parallel rays of light.
The image of a candle flame formed by a lens is obtained on a screen placed on the other side of the lens. If the image is three times the size of the flame and the distance between lens and image is 80cm, at what distance should the candle be placed from the lens? What is the nature of the image at a distance of 80cm and the lens?