CBSE Class 10 Science Set 2 Answer Key 2025 Unofficial (Available)

When a pure-tall pea plant is crossed with a pure-dwarf pea plant, the percentage of tall pea plants in F, and F2 generation pea plants will be respectively :

Plants like rose and banana have lost the capacity to produce :

In which one of the following situations a chemical reaction does not occur?

The property by virtue of which a solid material can be drawn into thin wires is called :

In order to prepare dry hydrogen chloride gas in humid atmosphere the gas produced is passed through a guard tube (drying tube) which contains :

Select from the following a hydrocarbon having one C-C bond and one

C=C bond :

Which one of the following has half the number of chromosomes and half the amount of DNA as compared to the non-reproductive body cells?

The essential element taken up from the soil by the plants to synthesize proteins is :

 Select TRUE statements about lymph from the following :
A. Lymph vessels carry lymph through the body and finally open into larger arteries.

B. Lymph contains some amount of plasma, proteins and blood cells.

C. Lymph contains some amount of plasma, proteins and red blood cells.

D. ymph vessels carry lymph through the body and finally open into larger veins.

Which one of the following gets biomagnified at different levels in a food chain ?

In the food chains given below. Select the most efficient food chain in terms of energy :

An optical device 'X' is placed obliquely in the path of a narrow parallel beam of light. If the emergent beam gets displaced laterally, the device 'X' is :

A piece of wire of resistance 'R' is cut lengthwise into three identical parts. These parts are then connected in parallel. If the equivalent resistance of this combination is R', then the value of R/R' is :

The minimum number of identical bulbs of rating 4V; 6W, that can work safely with desired brightness, when connected in series with a 240 V mains supply is :

An electric bulb is rated 220 V; 11W. The resistance of its filament when it glows with a power supply of 220 V is 

Assertion (A) : All exothermic reactions are accompanied with evolution
of heat and light.
Reason (R): Combination reactions may or may not be exothermic.

Assertion (A) : When ciliary muscles contract, eye lens becomes thin,
Reason (R): Ciliary muscles control the power of the eye lens.

Assertion (A): Concentrated nitric acid is diluted by adding water slowly to acid with constant stirring.
Reason (R): Concentrated nitric acid is easily soluble in water.

Assertion (A) : In reptiles, the temperature at which the fertilized eggs are kept decides the sex of the offsprings.
Reason (R): Sex is not genetically determined in some animals.