List of practice Questions

Natural ecosystem is —

Producer in a food chain is —

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.

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.

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?

The element having 7 electrons in its outermost orbit is —

Chemical formula of calcium nitrate is —

An unsaturated hydrocarbon in the following is —

Blood pressure is measured by —

Which of the following is a plant hormone?

Unisexual flower is —

The power of a lens is +2 dioptre. What will be its focal length in cm?

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

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?

In a conductor, 10 ampere of current is flowing. What will be the amount of charge flowing in 2 seconds corresponding to it?

The formula of plaster of Paris is —

The solution with pH 8.5 is —

IUPAC name of CH{3–CH(CH3)–CHO is —}

What is Ozone layer? Highlight its importance for Earth.

Write an essay on human hormones.

From which lens the image of object formed is virtual, erect and smaller than the object?

In a spherical mirror the distance between its centre of curvature and pole is 20 cm. What is the distance of focus from the pole of the mirror?

Due to which phenomenon of light does the sky appear blue?

Explain reactivity series and write its one use.

What do you understand by acid and base? Write two applications of pH in daily life.