Human Eye and Colourful World — Science STD 10 — Question

To determine the approximate focal length of the given convex lens by focussing a distant object (say, a sign board), you try to focus the image of the object on a screen. The image you obtain on the screen is always:

To convert an AC generator into DC generator:

A full length image of a distant tall building can definitely be seen by using:

Consider two statements A and B given below:

1. Real image is always inverted.
2. Virtual image is always erect.

Out of these two statements:

1. Only A is true.
2. Only B is true.
3. Both A and B are true.
4. None is true.

A student sitting on the last bench can read the letters written on the blackboard but is not able to read the letters written in his text book. Which of the following statements is correct?

A converging lens is used to produce an image of an object on a screen,object on a screen. What change is needed for the image to be formed nearer to the lens?

1. Increase the focal length of the lens.
2. Insert a diverging lens between the lens and the screen.
3. Increase the distance of the object from the lens.
4. Move the object closer to the lens.

A beam of white light falls on a glass prism. The colour of light which undergoes the least bending on passing through the glass prism is:

The sensation of vision in the retina is carries to the brain by:

A person finds difficulty in seeing nearby objects clearly. His vision can be corrected by using spectacles containing:

The image of an object formed by a plane mirror is:

1. Virtual.
2. Real.
3. Diminished.
4. Upside-down.