English Medium Class 10 - CBSE Important Questions

Which of the following pattern correctly describes the magnetic field around a long straight wire carrying current?

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.

Two LED bulbs of 10W and 5W are connected in series. If the current flowing through 5W bulb is 0.005A, the current flowing through 10W bulb is ______.

Refer to the image below and state how the magnetic field pattern indicates regions where the magnetic field is stronger outside the magnet. What happens to the magnetic field when the current in the circuit is reversed?

A rectangular loop ABCD carrying a current I is situated near a straight conductor XY, such that the conductor is parallel to the side AB of the loop and is in the plane of the loop. If a steady current I is established in the conductor as shown, the conductor XY will ______.

How is a solenoid prepared?

Differentiate between a circular coil and a solenoid.

What will be the amount of energy available to the organisms of the 2nd trophic level of a food chain if the energy available at the first trophic level is 10,000 joules?

Which of the following are always at the second tropic level of food chains?

State with reason any two possible consequences of elimination of decomposers from the Earth.

List two biotic components of a biosphere.

Why are green plants called producers?

The first trophic level in a food chain is always a green plant. Why ?

List two important roles play in the environment by decomposers.

Which of the following constitute a food-chain?

In the following food chain, 100 J of energy is available to the lion. How much energy was available to the producer?

Plants → Deer → Lion

In the following food chain, plants provide 500 J of energy to rats. How much energy will be available to hawks from snakes?

Plants → Rats → Snakes → Hawks 

In the following food chain, 20,000 J of energy was available to the plants. How much energy would be available to man in this chain?    
Plants → Sheep → Man

What are the various steps of food chain called?