Light – Reflection and Refraction — Science STD 10 — Question

A student wound an insulated copper wire around a soft iron rod. He then connected one end to the rheostat and the other free end to the battery via a key. He closed the key and observes the deflection in the magnetic needle placed nearby. Now he altered the current using by reversing the connections of the battery and again noted the change in the deflection of the needle.
i. Why do the student performed this activity?
ii. What did the student observe?
iii. Comment on the statement a material in the middle of a current carrying coil gets magnetised.

What is meant by a renewable source of energy? Give two examples of renewable sources of energy.

Why are electric bulbs filled with chemically inactive nitrogen and argon?

An object is placed at a distance of 40cm in front of a convex mirror of radius of curvature 40cm. List four characteristics of the image formed by the mirror.

A convex lens of power 5D and a concave lens of power 7.5D are placed in contact with each other. What is the:

1. Power of this combination of lenses?
2. Focal length of this combination of lenses?

Draw ray diagrams showing the image formation by a convex lens when an object is placed:
Between optical centre and focus of the lens.

How does the thickness of the eye lens change when we shift looking from a distant tree to reading a book?

Name some of the solar energy devices.

Name the type of magnet with which the magnetic field pattern of a current-carrying solenoid resembles.

Give two uses of a convex mirror. Explain why you would choose convex mirror for these uses.