Atoms and Molecules — Science STD 9 — Question

The radioactive isotope used in the treatment of cancer is:

1. Plutonium–239
2. Arsenic–74
3. Cobalt–60
4. Iodine–131

Larger the amplitude, ........ is the sound:

An apple of mass 100g falls from a tree because of gravitational attraction between the earth and the apple. If the magnitude of force exerted by the earth on the apple be F₁, and the magnitude of force exerted by the apple on the earth be F₂, then:

1. F₁ is very much greater than F₂
2. F₂ is very much greater than F₁
3. F₁ is only a little greater than F₂
4. F₁ and F₂ are exactly equal.

A sprinter is running along the circumference of a big sports stadium with constant speed Which of following do you think is changing in this case?

1. Magnitude of acceleration being produced.
2. Distance covered by the sprinter per second.
3. Direction in which the sprinter is running.
4. Entripetal force acting on the sprit.

Sounds having frequency more than 20,000 Hz are called:

Identify the correct statement about cells.

Identify the group among the following, which contains only micronutrients:

Howis a bacterial cell different from an onion peel cell?

The cause of floating of clouds in atmosphere is:

Soil is the component of:

1. Atmosphere.
2. Hydrosphere.
3. Lithosphere.
4. None of the above.