Magnetic Effects of Electric Current — Science STD 10 — Question

What is the role of hydrochloric acid in our stomach?

What measures would you take to conserve electricity in your house?

Differentiate between ureter and urethra.

Lithium, sodium and potassium are all metals that react with water to liberate hydrogen gas. Is there any similarity in the atoms of these elements? Explain your answer.

Name any four types of ornamental plants which are being produced by tissue culture technique.

To find the image distance for varying object distances in case of a convex lens of focal length 15 cm, a student obtains on a screen a sharp image of a bright object by placing it at 20 cm distance from the lens. After that he gradually moves the object away from the lens and each time focuses the image on the screen.

1. In which direction-towards or away from the lens does he move the screen to focus the object?
2. How does the size of image change?
3. Approximately at what distance does he obtain the image of magnification -1?
4. How does the intensity of image change as the object moves farther and farther away from the lens?

A 4 cm tall object is placed on the principal axis of a convex lens. The distance of the object from the optical centre of the lens is 12cm and its sharp image is formed at a distance of 24cm from it on a screen on the other side of the lens. If the object is now moved a little away from the lens, in which way (towards the lens or away from the lens) will he have to move the screen to get a sharp image of the object on it again? How will the magnification of the image be affected?

In the straight wire A, current is flowing in the vertically downwards direction whereas in wire B the current is flowing in the vertically upward direction. What is the direction of magnetic field:

1. In wire A?
2. In wire B?

Name the rule which you have used to get the answer.

Give a chemical reaction to prove that non-metallic oxides are acidic in nature.