The Fundamental Unit of Life — Science STD 9 — Question

Which of the following factors are responsible for the change in state of solid carbon dioxide when kept exposed to air?

1. Increase in pressure
2. Increase in temperature
3. Decrease in pressure
4. Decrease in temperature

1. (i) and (ii)
2. (i) and (iii)
3. (ii) and (iii)
4. (ii) and (iv)

Of the following substance which is an element, a mixture and a compound?
Sea water is the example of:

In case of negative work, the angle between the force and displacement is :

When sugar is dissolved in water, the level of water _________?

To solve the food problem of the country, which among the following is necessary?

The speeds of sound in four different media are given below. Which of the following is the most likely speed in m/s with which the two under water whales in a sea talk to each other when separated by a large distance?

A man is stranded in the middle of a perfectly smooth island of ice, where there is no friction between the ground and his feet. Under these circumstances,

Which of the following is not a biotic resistance factor that affects plants?

The frequencies of four sound waves are given below. Which of these sound waves can be used to measure the depth of sea by the echo method?

1. 15,000Hz
2. 10kHz
3. 50kHz
4. 10,000Hz

Which is the most simple type of motion among the following?