List of top Science Questions

Write short notes on the following:
(i) pH value
(ii) Oxidation reaction
(iii) Combustion reaction

Write the chemical equations for two chemical properties of ethanol.

Write the chemical equations for two chemical properties of acetic acid.

State the following laws with the help of labelled diagram. With the help of the following, the direction of which physical quantity can be known?
(i) Fleming’s Left Hand Rule
(ii) Right Hand Thumb Rule

Explain the following:
(a) Double decomposition reaction
(b) Neutralization reaction

Explain corrosion by giving example.

Write the use of bleaching powder in purification of water.

Write the chemical equation for obtaining gypsum from plaster of Paris.

What are the defects of vision? Write down the names of the lenses used for the correction of vision defect of three persons P, Q, and R if —
(i) \( P \) can see only near objects clearly but cannot see far objects.
(ii) \( Q \) can see only far objects clearly but cannot see near objects.
(iii) \( R \) can neither see far objects nor near objects clearly.

Producer in a food chain is —

The speeds of light in water and glass are respectively \( 2.25 \times 10^8 \, \text{m/s} \) and \( 2.0 \times 10^8 \, \text{m/s} \). Calculate the following refractive indices:
(i) The glass relative to water.
(ii) The glass relative to air.

Natural ecosystem is —

Example of regeneration is —

The resistance of a conductor depends on which factors and how? The resistance of a wire is \( R \). What will be the resistance of the wire when the wire is of double length and half the radius of the same material?

Depletion of ozone layer is caused by which of the following?

An unsaturated hydrocarbon in the following is —

Blood pressure is measured by —

Unisexual flower is —

Which of the following is a plant hormone?

Chemical formula of calcium nitrate is —

The element having 7 electrons in its outermost orbit is —

The solution with pH 8.5 is —

In which of the following wires of domestic electric distribution is the fuse wire connected in series?

The formula of plaster of Paris is —

If the units of power, work, and time are represented by \( x_1, x_2, x_3 \) respectively, then which of the following relations is correct?