English Medium इयत्ता १० - CBSE Question Bank Solutions for Science

A light ray enters from medium A to medium B as shown in Figure 10.2. The refractive index of medium B relative to A will be

Beams of light are incident through the holes A and B and emerge out of box through the holes C and D respectively as shown in the Figure Which of the following could be inside the box?

A beam of light is incident through the holes on side A and emerges out of the holes on the other face of the box as shown in the Figure. Which of the following could be inside the box?

A magnetic compass needle is placed in the plane of paper near point A as shown in Figure. In which plane should a straight current carrying conductor be placed so that it passes through A and there is no change in the deflection of the compass? Under what condition is the deflection maximum and why?

AB is a current carrying conductor in the plane of the paper as shown in Figure. What are the directions of magnetic fields produced by it at points P and Q? Given r₁ > r₂, where will the strength of the magnetic field be larger?

In a food chain, the third trophic level is always occupied by

In the given food chain, suppose the amount of energy at the fourth trophic level is 5 kJ, what will be the energy available at the producer level?

Grass → Grasshopper → Frog → Snake → Hawk

Accumulation of non-biodegradable pesticides in the food chain in increasing amount at each higher trophic level is known as

Which group of organisms are not constituents of a food chain?

1. Grass, lion, rabbit, wolf
2. Plankton, man, fish, grasshopper
3. Wolf, grass, snake, tiger
4. Frog, snake, eagle, grass, grasshopper

What will happen if deer is missing in the food chain given below?

Grass → Deer → Tiger

The table shows the electronic structures of four elements. 

1.  Identify which element(s) will form covalent bonds with carbon.
2. “Carbon reacts with an element in the above table to form several compounds.” Give suitable reason.

DDT was sprayed in a lake to regulate breeding of mosquitoes. How would it affect the trophic levels in the following food chain associated with a lake? Justify your answer.

In the following food chain, vertical arrows indicate the energy lost to the environment and horizontal arrows indicate energy transferred to the next trophic level. Which one of the three vertical arrows (A, C and E) and which one of the two horizontal arrows (B and D) will represent more energy transfer? Give reason for your answer.

A food chain in a forest ecosystem

Which of the following is the correct observation of the reaction shown in the above set up?

These consist of two statements – Assertion (A) and Reason (R). Answer these questions selecting the appropriate option given below:

Assertion: On freely suspending a current – carrying solenoid, it comes to rest in Geographical N-S direction.

Reason: One end of current carrying straight solenoid behaves as a North pole and the other end as a South pole, just like a bar magnet.

A compass needle is placed near a current carrying wire. State your observations for the following cases and give reasons for the same in each case -

1. Magnitude of electric current in wire is increased.
2. The compass needle is displaced away from the wire.

"Carbon prefers to share its valence electrons with other atoms of carbon or with atoms of other elements rather than gaining or losing the valence electrons in order to attain noble gas configuration." Give reasons to justify this statement.