10th Standard Science First Midterm Exam 2026 – Important Questions & Answers PDF | Kalvi Mini

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10th Science First Midterm Exam 2026 – Full Answer Key

FIRST MID TERM TEST - 2026

Standard - X

SCIENCE

Time: 1.30 hrs

Marks: 50

1 Inertia of a body depends on ___________ Answer: c) mass of the object

2 Impulse is equal to ___________ Answer: c) change of momentum

3 Power of lens is -4D, then the focal length is ___________ Answer: c) -0.25m

4 Mass of 1 mole of nitrogen atom is ___________ Answer: d) 14g

5 ___________ group contains the member of halogen family. Answer: a) 17th

6 The endarch condition is the characteristic feature of ___________ Answer: b) stem

7 Kreb's cycle takes place in ___________ Answer: b) mitochondria matrix

8 Mammals are ___________ animals. Answer: b) Warm blooded

9 ___________ is an important metal to form amalgam. Answer: b) Hg

Part – II

10. Fill in the blanks.

i) Glycolysis takes place in cytoplasm.

ii) The blood sucking habit of leech is known as sanguivorous.

11. Classify the types of force based on their classification.

Based on the direction in which the forces act, they can be classified into two types as:

(a) Like parallel forces: Two or more forces of equal or unequal magnitude acting along the same direction, parallel to each other.

(b) Unlike parallel forces: If two or more equal or unequal forces act along opposite directions, parallel to each other.

12. What are the causes of Myopia?

Myopia occurs due to the lengthening of eye ball.

The focal length of eye lens is reduced or the distance between eye lens and retina increases.

Due to this, the image of distant objects are formed before the retina.

13. Name the acid that renders Aluminium passive. Why?

Nitric acid (HNO₃) renders aluminium passive.

It renders aluminium passive due to the formation of an oxide film on its surface.

14. What is respiratory quotient?

Respiratory quotient is the ratio of volume of carbon dioxide liberated to the volume of oxygen consumed during respiration.

RQ = ^{Volume of CO₂ liberated}⁄_{Volume of O₂ consumed}

15. Calculate the Gram Molecular Mass of:

i) H₂O

Gram Molecular Mass of H₂O = 18 g.

ii) CO₂

Gram Molecular Mass of CO₂ = 44 g.

Part – III

16. Differentiate Mass and Weight.

S.No	Mass	Weight
1	Mass is defined as the quantity of matter contained in the body.	Weight is defined as the gravitational force exerted on a body due to gravity.
2	Its SI unit is kilogram (kg).	SI unit of weight is newton (N).
3	Mass of a body remains the same at all places (both on the Earth and the Moon).	Weight of a body varies from one place to another on the Earth since it depends on 'g'.
4	It is a scalar quantity.	Weight is a vector quantity.

17. Write any 4 properties of light.

Light is a form of energy.
Light always travels along a straight line.
Light does not need any medium for its propagation; it can even travel through vacuum.
The speed of light in vacuum or air is c = 3 × 10⁸ ms⁻¹.

18. What is rust? Write the equation for the formation of rust.

When iron is exposed to moist air, it forms a layer of brown hydrated ferric oxide on its surface.

This compound is known as rust and the phenomenon of its formation is known as rusting.

Equation:

4Fe + 3O₂ + xH₂O → 2Fe₂O₃·xH₂O (rust)

19. Name the three basic tissue system in flowering plants.

Sachs classified the tissue system in plants into three types:

Dermal or Epidermal tissue system.
Ground tissue system.
Vascular tissue system.

20.

i) Draw and label the structure of Oxysomes.

The inner mitochondrial membrane bears minute regularly spaced tennis racket-shaped particles known as oxysomes (F₁ particle).

Labels:

Head (F₁)
Stalk
Base (F₀)

ii) Write the overall reaction for photosynthesis.

6CO₂ + 12H₂O → C₆H₁₂O₆ + 6O₂ ↑ + 6H₂O

(Light, chlorophyll)

(Carbon dioxide + Water → Glucose + Oxygen + Water)

Part – IV

21. a) State Newton's Laws of Motion.

Newton's First Law:

This law states that every body continues to be in its state of rest or the state of uniform motion along a straight line unless it is acted upon by some external force.

It gives the definition of force as well as inertia.

Newton's Second Law:

According to this law, the force acting on a body is directly proportional to the rate of change of linear momentum of the body and the change in momentum takes place in the direction of the force.

Formula:

F = m × a

Newton's Third Law:

Newton's third law states that for every action, there is an equal and opposite reaction. They always act on two different bodies.

If a body A applies a force F_A on a body B, then body B reacts with force F_B on body A, which is equal in magnitude but opposite in direction.

F_B = −F_A

(OR)

21. b) Explain the rules for obtaining images formed by a convex lens with the help of a ray diagram.

The position, size and nature of the image formed by a convex lens can be understood using the following rules:

Rule – 1: When a ray of light strikes the convex lens obliquely at its optical centre (O), it continues along the same path without any deviation.

Rule – 2: When rays parallel to the principal axis strike a convex lens, the refracted rays converge at the principal focus (F) on the other side of the lens.

Rule – 3: When a ray passing through the principal focus strikes a convex lens, the refracted ray becomes parallel to the principal axis.

Draw the corresponding ray diagrams.

22. a)

i) Define Atomicity.

The number of atoms present in a molecule is called its atomicity.

ii) State the postulates of Modern Atomic Theory.

An atom is no longer indivisible.
Atoms of the same element may have different atomic masses.
Atoms of different elements may have the same atomic masses.
Atoms of one element can be transmuted into atoms of other elements.
Atoms may not always combine in a simple whole number ratio.
Atom is the smallest particle that takes part in a chemical reaction.
The mass of an atom can be converted into energy (E = mc²).

(OR)

22. b) What is an alloy? What are the reasons for alloying?

Alloy:

An alloy is a homogeneous mixture of two or more metals or of one or more metals with certain non-metallic elements.

Reasons for alloying:

To modify appearance and colour.
To modify chemical activity.
To lower the melting point.
To increase hardness and tensile strength.
To increase resistance to electricity.

23. a)

i) Differentiate Monocot Root and Dicot Root.

S.No	Features	Dicot Root	Monocot Root
1	Xylem	Tetrarch (four bundles)	Polyarch (many bundles)
2	Cambium	Present (during secondary growth)	Absent
3	Secondary growth	Present	Absent
4	Pith	Absent or small	Large and well-developed

ii) Differentiate Aerobic Respiration and Anaerobic Respiration.

S.No	Aerobic Respiration	Anaerobic Respiration
1	Occurs in the presence of oxygen.	Occurs in the absence of oxygen.
2	Food is completely oxidized to CO₂ and H₂O.	Food is partially oxidized to ethanol or lactic acid.
3	Produces a large amount of energy (ATP).	Produces a very small amount of energy (ATP).

(OR)

23. b)

i) How does leech respire?

In leech, respiration takes place through the skin (integument).

The skin is very thin and moist and is supplied with a network of tiny blood vessels (capillaries) to facilitate the exchange of gases.

ii) List out the parasitic adaptations in leech.

Suckers: Presence of anterior and posterior suckers for attachment to the host.
Jaws: Three jaws inside the mouth make a Y-shaped wound on the host's skin.
Hirudin: Salivary glands produce an anticoagulant called hirudin, which prevents blood from clotting while sucking.
Pharynx: The muscular pharynx acts as a suction pump to suck blood.
Crop: The crop stores large quantities of sucked blood, which can be digested slowly over several months.
Parapodia/Setae: These are absent because they are not required for its parasitic life.

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