The Fundamental Unit of Life — Science STD 9 — Question

Cork cambium is an example of-

Bats detect the obstacles in their path by receiving the reflected:

Sum of atomic masses of all atoms in a formula unit of an ionic compound is known as :

Which one of the following is not a chemical change?

1. Formation of curd.
2. Ripening of banana..
3. Sublimation of naphthalene.
4. Corrosion of photo frame.

An elevator with load, weighing 500kg is moving up with a velocity of 0.2ms. The power of the motor in horse power is (1H.P. = 746 watt):

Newton's law of gravitation holds good for:

Two chemical substances X and Y combine together to form a product P which contains both X and Y
X + Y → P
X and Y cannot be broken down into simpler substances by simple chemical reactions. Which of the following statements concerning X, Y and P are correct?

1. P is a compound.
2. X and Y are compound.
3. X and Y are elements.
4. P has a fixed composition.

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

The atoms of which of the following pair of elements are most likely to exist in free state?

Which of the following frequency of sound can be generated by a vibrating simple pendulum as well as by the vibrating vocal cords of a rhinoceros?

In a sample of ethyl ethanoate (CH₃COOC₂H₂), the two oxygen atoms have the same number of electrons but different number of neutrons. Which of the following is the correct reason for it?

1. One of the oxygen atoms has gained electrons.
2. One of the oxygen atoms has gained protons.
3. The two oxygen atoms are isotopes.
4. The two oxygen atoms are isobars.