Magnetic Effects of Electric Current — Science STD 10 — Question

A student obtained a sharp image of a burning candle, placed at the farther end of a laboratory table, on a screen using a concave mirror. For getting better value of focal length of the mirror, the subject teacher suggested him for focusing a well illuminated distant object. What should the student do?

A positively charged particle (proton) is projected towards east.The magnetic field is towards south.The particle will be deflected towards:

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 current-carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should passed in the conductor:

1. From top towards bottom.
2. From left towards right.
3. From bottom towards top.
4. From right towards left.

A series of fast-moving still pictures can create an illusion of movement because:

A teacher sets up the stand carrying a convex lens of focal length 15cm at 42.7cm 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. 12.7cm.
2. 29.7cm.
3. 57.7cm.
4. 72.7cm.

The correct position of the screen was suggested by.

Electric power is inversely proportional to:

Red light is used as danger signal because it is:

A concave mirror cannot be used as:

1. A magnifying mirror
2. A torch reflector
3. A dentist's mirror
4. A real view mirror

Which of the following can make a parallel beam of light from a bulb falls on it?