English Medium Class 10 - CBSE Question Bank Solutions

Observe the food web and answer the questions given below:

Which trophic level is incorrectly defined?

Draw ray diagram showing hypermetropic eye.

Choose the incorrect statement

A constant current flows in a horizontal wire in the plane of the paper from east to west as shown in Figure. The direction of magnetic field at a point will be North to South

The strength of magnetic field inside a long current carrying straight solenoid is

Which of the following limits the number of trophic levels in a food chain?

In the given figure the various trophic levels are shown in a pyramid. At which trophic level is maximum energy available?

Suggest one word for the following statement/definition.

Each level of food chain where transfer of energy takes place

Why are autotrophs considered to be at the first trophic level of all food chains?

State the reason for limited number of trophic levels in nature.

Consider the following chemical equation I and II

1. \[\ce{Mg + 2HCl -> MgCl_2 +H_2}\]
2. \[\ce{NaOH +HCl -> NaCl + H_2O}\]

The correct statement about these equations is:

Why do different food chains in an ecosystem not have more than four to five trophic levels? Give reason.

State the change in colour observed in following case mentioning the reason:

A piece of zinc is dipped in ferrous sulphate solution.

List two difference in the characteristic properties of the virtual images formed by the two types of spherical lenses (concave and convex). How are these characteristics of the two lenses use in the correction of the two common defects of vision namely myopia and hypermetropia?

The colour of the solution observed after 30 minutes of placing zinc metal in copper sulphate solution is ______.

Give an example of a double displacement reaction other than the one given in the following Activity.
•Take about 3 mL of sodium sulphate
solution in a test tube.
• In another test tube, take about 3 mL of
barium chloride solution.
• Mix the two solutions given in the following fig.
• What do you observe?

Write the balanced chemical equation for the following and identify the type of reaction. 

\[\ce{Potassium bromide (aq) + Barium iodide (aq) -> Potassium iodide (aq) + Barium bromide (s)}\]

What is the difference between displacement and double displacement reactions? Write equations for these reactions.

What do you mean by a precipitation reaction? Explain giving an example.

A person needs a lens of power -5.5 dioptres for correcting his distant vision. For correcting his near vision he needs a lens of power +1.5 dioptre. What is the focal length of the lens required for correcting (i) distant vision and (ii) near vision?