Human Eye and Colourful World — Science STD 10 — Question

A teacher sets up the stand carrying a convex lens of focal length 15 cm at 42.7 cm mark on the optical bench. He asks four students A, B, C and D to suggest the position of screen on the optical bench so that a distinct image of a distant tree is obtained almost immediately on it. The positions suggested by the students were as:

1. 12.7 cm.
2. 29.7 cm.
3. 57.7 cm.
4. 72.7 cm.

The correct position of the screen was suggested by.

The diagram given below represents magnetic field caused by a current-carrying conductor which is:

When a person is myopic, he/ she can clearly see:

In the concave reflector of a torch, the bulb is placed:

1. Between the pole and focus of reflector.
2. At the focus of reflector.
3. Between focus and centre of curvature of reflector.
4. At the centre of curvature of reflector.

The splitting up of white light into seven colours on passing through a glass prism is called:

1. Refraction.
2. Deflection.
3. Dispersion.
4. Scattering.

Which of the following coloured light has the least speed in glass prism?

Two parallel conductors A and B of equal lengths carry currents I and 10I respectively in the same direction. Then

Advanced sunrise and delayed sunset is due to ________ of sunlight:

Which of the following statement is correct?

Out of the following, the colour of light having the maximum wavelength is: