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In the circuit shown in the figure, when the switch is moved to ‘ON’ position, (a) the bulb A will glow first (b) the bulb B will glow first (c) the bulb C will glow first (d) all bulbs will glow together

For a bulb to glow the circuit must be complete. Option (a) states that bulb A will glow but the bulb A will not glow until the circuit... View Article

In the following arrangement shown in the figure, the bulb will not glow if the ends A and B are connected with (a) A steel spoon (b) A metal clip (c) A plastic clip (d) A copper wire

Steel spoon, metal clip, and copper wire all or made of metal while the plastic clip is a non-metal thing. And we know that only metals conduct... View Article

In an electric bulb, light is produced due to the glowing of (a) the glass case of the bulb (b) the thin filament (c) the thick wires supporting the filament (d) gases inside glass case of the bulb.

b) The thin filament. There is a thin filament present inside a bulb that glows and produces light. The light bulb consists of three key... View Article

Choose the incorrect statement. (a) A switch is the source of electric current in a circuit. (b) A switch helps to complete or break the circuit. (c) A switch helps us to use electricity as per our requirement. (d) When the switch is open there is an air gap between its terminals.

a) A switch is the source of electric current in a circuit The most common form of the electric power switch is a basic manual... View Article

Choose from the options a, b, c and d given in the figurewhich shows the correct direction of current.

In an electric circuit, there is a cell which has two terminals, positive and negative. The current leaves from the positive terminal and enters... View Article

A sheet of plywood, a piece of muslin cloth and that of a transparent glass, all of the same size and shape were placed at A one by one in the arrangement shown in fig 11.12. Will the shadow be formed in each case? If yes, how will the shadow on the screen be different in each case? Give reasons for your answer.

Shadow formation takes place when an object completely or partially blocks the rays that are coming on it. Lighter image will be formed of... View Article

A student had a ball, a screen and a torch in working condition. He tried to form a shadow of the ball on the screen by placing them at different positions. Sometimes the shadow was not obtained. Explain.

Following are the same reasons due to which the shadow cannot be obtained: He cannot get shadow on the screen if the screen is placed far away... View Article

A football match is being played at night in a stadium with flood lights ON. You can see the shadow of a football kept at the ground but cannot see its shadow when it is kicked high in the air. Explain.

The ground acts as a screen for the ball lying on ground as the lights are falling on the opaque object. But the shadow disappears with the... View Article

In the given figure, a flower made of thick coloured paper has been pasted on the transparent glass sheet. What will be the shape and colour of shadow seen on the screen?

The shadow formed will be of the shape of the flower with its stalk, but, dark in colour.Shadow is the dark patch formed when an object obstructs... View Article

Using a pinhole camera a student observes the image of two of his friends, standing in sunlight, wearing yellow and red shirt respectively. What will be the colours of the shirts in the image?

Pinhole camera does not change the colour of the image and it is the same as that of the object. But, image formed is inverted and left - right... View Article

Three identical towels of red, blue and green colours are hanging on a clothes line in the sun. What would be the colour of shadows of these towels?

Shadow is the dark patch formed when an object obstructs the path of the light. Hence, no light reaches in the shadow region due to which the... View Article

Is air around us always transparent? Discuss.

Air around us is transparent due to which we can see the objects like trees, buildings, etc. But when the thick smoke, clouds, dust is present in... View Article

A student covered a torch with red cellophane sheet to obtain red light. Using the red light she obtains a shadow of an opaque object. She repeats this activity with green and blue light. Will the colour of the light affect the shadow? Explain.

No the color of the light will not affect the shadow because .Shadow is the dark patch formed when an object obstructs the path of the light.... View Article

You are given a transparent glass sheet. Suggest any two ways to make it translucent without breaking it.

A transparent glass can be changed into translucent sheet by- i. Butter or oil could be applied which will make it partially permeable. ii.... View Article

On a sunny day, does a bird or an aeroplane flying high in the sky cast its shadow on the ground? Under what circumstances can we see their shadow on the ground?

The bird or an airplane flying high in the sky do not cast their shadow on the ground because they are at very high altitude due to which the... View Article

Suggest a situation where we obtain more than one shadow of an object at a time.

The multiple shadows at a time of an object can be obtained when the light falls on the same object from different sources at a time like torch,... View Article

Correct the following statements. (i) The colour of the shadow of an object depends on its colour of the object. (ii) Transparent objects allow light to pass through them partially.

i) No, the colour of the object does not affect the colour of the image, because the shadow formed in always dark or black in colour. Shadow is... View Article

Look at the given figure. Will there be any difference in the shadow formed on the screen in A and B?

The same shadow will be formed on screen A and B because formation of the image depends on the size and shape of the opaque object. As the same... View Article

Three torches A, B and C shown in the figure are switched on one by one. The light from which of the torches will not form a shadow of the ball on the screen.

Torch A and B are placed in front of the screen so they will form image. As torch C is placed parallel to the screen, it will not form a shadow... View Article

Observe the picture given in figure A sheet of some material is placed at position ‘P’, still the patch of light is obtained on the screen. What is the type of material of this sheet?

P is the sheet of some transparent material like thin plastic, ground glass etc. Because only the transparent materials allows light to pass... View Article

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