Light – Reflection and Refraction — Science STD 10 — Question

Which of the following diagrams shows the ray of light refracted correctly?

Give the law of combination of resistances in series.

An object is placed at the following distance from a convex lens of focal length 15cm:

1. 35cm
2. 30cm
3. 20cm
4. 10cm

Which position of the object will produce:

1. A magnified real image?
2. A magnified virtual image?
3. A diminished real image?
4. An image of same size as the object?

How is the amount of light entering the eye controlled?

What shape are your eye-lenses:

1. When you look at your hand?
2. When you look at a distant tree?

Draw a diagram to show the magnetic field lines around a bar magnet.

Compute the heat generated while transferring 96000 coulomb of charge in one hour through a potential difference of 50 V.

An air-conditioner of 3.2kW power rating is connected to a domestic electric circuit having a current rating of 10A. The voltage of power supply is 220V. What will happen this air-conditioner is switched on? Explain your answer.

To find-the image-distance for varying object-distances in case of a convex lens, a student obtains on a screen a sharp image of a bright object placed very far from the lens. After that he gradually moves the object towards the lens and each time focuses its image of the screen.

1. In which direction - towards or away from the lens, does he move the screen to focus the object?
2. What happens to the size of the image - does it increase or decrease?
3. What happen when he moves the object very close to the lens?

Give the relationship between the wavelength of light and its angle of deviation, when it is passed through a prism.