Matter in Our Surroundings — Science STD 9 — Question

Explain why, osmosis can be considered to be a special kind of diffusion. Classify the following into (i) osmosis, and (ii) diffusion:

1. Swelling up of a raisin on keeping in water.
2. Spreading of virus on sneezing.
3. Earthworm dying on coming in contact with common salt.
4. Shrinking of grapes kept in thick sugar syrup.
5. Preserving of pickles in salt.
6. Spreading of smell of cake being baked in the kitchen.
7. Aquatic animals using oxygen dissolved in water during respiration.

Draw a flow diagram of the processes involved in obtaining gases like nitrogen, oxygen and argon from air.

A device called oscillator is used to send waves along a stretched string. The string is 20cm long, and four complete waves fit along its length when the oscillator vibrates 30 times per second. For the waves on the string:

1. What is their wavelength?
2. What is their frequency?
3. What is their speed?

How would you obtain sodium chloride from a mixture of sodium chloride and sulphur without using water?

Draw a labeled diagram of the experimental set-up to study the latent heat of vaporization of water.

Describe how the gravitational force between two objects depends on the distance between them.

A bus was moving with a speed of 54km/h. On applying brakes it stopped in 8 seconds. Calculate the acceleration.