Life Processes — Science STD 10 — Question

If a milky of cloudy membrane grow over the eye lens, then which defect is the person suffering from?

Write the names and structural formulae of all the possible isomers of hexane.

List two properties of the images formed by convex mirrors. Draw ray diagram in support of your answer.

State two advantages of conserving (i) forests, and (ii) wild-life.

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?

Arrange the terms in correct sequence:
Glomerulus, renal vein, efferent arterioles, renal artery, afferent arterioles, secondary capillaries.

How is charcoal obtained from wood? Why is charcoal considered a better fuel than wood?

i. Why does carbon form the largest number of compounds? Give two reasons.
ii. Why are some of these called saturated and the other unsaturated compounds?
iii. Which one of these two is more reactive and why?

The electronic configurations of two elements A and B are given below:
A 2, 6
B 2, 8, 1
What type of chemical bond is formed between the two atoms of A?
What type of chemical bond will be formed between the atoms of A and B?

Why does the cord of an electric heater not glow while the heating element does?