Karnataka SSLC Science Mid-Term Question Paper 2025-26 with Answer Key: Download PDF

Particulars

Details

Exam Name

Karnataka SSLC (Class 10) Mid-Term Examination 2025-26

Conducting Body

Karnataka School Examination and Assessment Board (KSEAB)

Applicable Schools

All Government, Aided, and Private Schools affiliated to KSEAB

Official Website

https://kseab.karnataka.gov.in

Class

Class 10 (SSLC)

Exam Date

13th September, 2025

Duration

10:30 AM to 1:45 PM

Total Theory Marks

80

Sections Covered

Biology, Chemistry, Physics

Question Pattern

Combination of Multiple Choice Questions (MCQs), Short Answer, Long Answer

Difficulty Level

Moderate: balanced between conceptual, application, and memory-based questions

Part A (PHYSICS)

I. Four alternatives are given for each of the following questions / incomplete statements. Choose the correct alternative and write the complete answer along with its letter of alphabet. (2 x 1 = 2)

1. The field lines inside a current carrying solenoid are parallel. Hence the magnetic field inside the solenoid is
   (A) very high
   (B) equal
   (C) zero
   (D) very low

2. An electric current flowing through a conductor for 2 seconds generates J joules of heat. If the current flowing through the same conductor is doubled and passed for 1/2 a second, then the amount of heat generated is
   (A) J/2
   (B) J
   (C) 2J
   (D) 4J

II. Answer the following questions: (3 x 1 = 3)

3. Name the device used to vary resistance in an electric circuit.

4. Why does a magnetic needle brought near a bar magnet deflect?

5. A part of a diagram showing the flow of current in a circuit is given:

If I1>I2, I4>I3 and I2=2I4 then the resistance of which resistor is more?

III. Answer the following questions: (2×2=4)

6. Observe the figure of a bar magnet given below. Between the points A and B, in which of the points is the magnitude of the magnetic field lesser? Mention the reason.

7. State Joule's law of heating. Write the mathematical form of this law.

OR

State Ohm's law. Define 1 'ohm'.

IV. Answer the following questions: (3×3=9)

8. Draw the schematic diagram of an electric circuit consisting of resistors R1, R2 and R3 connected in series, a battery, a switch and the devices used to measure the potential difference of the total resistance and electric current.

9. State Right hand thumb rule. Write four characteristics of magnetic field lines.

OR

State Fleming's left hand rule. Write the characteristics of magnetic field lines formed around a current carrying circular loop.

10. a) Find the amount of charges flowing in a circuit if 1A of current flows for 5 minutes in the circuit.

b) If 2 joules of work is done in bringing 1 coulomb of charge from one point to another, then what is the potential difference between those two points?

OR

a) Find the work done if 9 C of charge moves between two points having a potential difference of 9 V.

b) What is the electric current if 3 C of charge flows through a point in 3 sec in an electric circuit?

V. Answer the following question : (1 x 4 = 4)

11. a) What is overload? What are the causes for overloading in domestic electric circuits?

b) What is the function of an earth wire?

VI. Answer the following question: (1 x 5 = 5)

12. a) What is electric power? Which is the SI unit of electric power? Write the three formulas used to calculate electric power.

b) What is the function of a fuse? What is the difference between the wire used in the filaments of bulbs and the wire used in the fuses with respect to their melting points?

Karnataka SSLC Science Mid-Term Exam Question Paper 2025: Download PDF

Part A: Physics

I. Multiple Choice Questions

1. Answer: (B) equal

2. Answer: (B) J

II. Short Answer Questions

3. The device used to vary resistance in an electric circuit is a rheostat or variable resistor.

4. A magnetic needle is a small magnet. When it is brought near another magnet, such as a bar magnet, the magnetic field lines from the bar magnet exert a force on the poles of the magnetic needle. The north pole of the needle is attracted to the south pole of the bar magnet and repelled by its north pole, causing the needle to deflect and align with the magnetic field lines.

5. The question as written contains contradictory information. Assuming a likely interpretation where I2 is the total current in the top parallel branch and I4 is the total current in the bottom parallel branch, the condition I2=2I4 means that the top branch has twice the current of the bottom branch. In a parallel circuit, current is inversely proportional to resistance (I=V/R). Therefore, the branch with a higher current must have a lower total resistance.

• Given: Itop branch=2Ibottom branch

• Therefore: Rtop branch=21Rbottom branch

• R1+R2<R3+R4

• The question asks which resistor has more resistance, which cannot be determined from the given information. However, the total resistance of the bottom branch (R3+R4) is greater than the total resistance of the top branch (R1+R2).

III. Answer the following questions: (2×2=4)

6. The magnitude of the magnetic field is lesser at point A.

• The magnetic field lines are densest at the poles of a bar magnet and spread out as they move away.

• Point A is farther away from the poles than point B. Therefore, the magnetic field lines are less crowded at point A, indicating a weaker magnetic field.

7. Joule's Law of Heating: This law states that the heat generated in a conductor is directly proportional to the square of the current flowing through it, the resistance of the conductor, and the time for which the current flows.

• Mathematical form: H=I2Rt
  OR
  Ohm's Law: This law states that the potential difference (voltage) across a conductor is directly proportional to the current flowing through it, provided all physical conditions and temperature remain constant.

• Mathematical form: V=IR

• Definition of 1 'ohm': One ohm (1Ω) is the resistance of a conductor through which a current of one ampere flows when a potential difference of one volt is applied across its ends.

IV. Answer the following questions: (3×3=9)

8. The schematic diagram would be drawn as follows:

• A battery symbol (a long line and a short line) is connected to a switch.

• The switch is then connected to three resistors (R1, R2, R3) placed end-to-end, which represents them being in series.

• An ammeter (labeled 'A' in a circle) is connected in series anywhere in the circuit to measure the current.

• A voltmeter (labeled 'V' in a circle) is connected in parallel across the entire series combination of resistors to measure the total potential difference

9. Right-Hand Thumb Rule: If you hold a current-carrying straight conductor in your right hand, with your thumb pointing in the direction of the current, then the direction in which your fingers curl around the conductor gives the direction of the magnetic field lines.

• Four Characteristics of Magnetic Field Lines:

1. They are continuous closed curves.

2. They emerge from the North pole and merge into the South pole outside the magnet, and inside the magnet, they are from the South pole to the North pole.

3. They never intersect with each other.

4. The density of the field lines indicates the strength of the magnetic field; denser lines mean a stronger field.

OR

Fleming's Left-Hand Rule: This rule is used to determine the direction of the force experienced by a current-carrying conductor when placed in an external magnetic field.

• Stretch the thumb, forefinger, and middle finger of your left hand so that they are mutually perpendicular.

• If the forefinger points in the direction of the magnetic field, and the middle finger points in the direction of the current, then the thumb will point in the direction of the Force (or motion).

• Characteristics of Magnetic Field Lines around a Circular Loop:

1. The magnetic field lines are concentric circles near the wire.

2. As you move towards the center of the loop, the field lines become less curved and appear almost straight and parallel to each other.

3. At the center of the loop, the magnetic field lines are straight and perpendicular to the plane of the loop.

4. The direction of the field lines can be determined by the Right-Hand Thumb Rule, where the fingers curl in the direction of the current and the thumb points in the direction of the field.

10. a) Find the amount of charge flowing:

• Given: Current (I) = 1 A, Time (t) = 5 minutes = 5×60=300 seconds.

• Formula: Q=I×t

• Calculation: Q=1 A×300 s=300 C.

• Answer: The amount of charge flowing is 300 Coulombs.

b) Find the potential difference:

• Given: Work done (W) = 2 J, Charge (Q) = 1 C.

• Formula: V=W/Q

• Calculation: V=2 J/1 C=2 V.

• Answer: The potential difference is 2 Volts.

OR

a) Find the work done:

• Given: Charge (Q) = 9 C, Potential Difference (V) = 9 V.

• Formula: W=V×Q

• Calculation: W=9 V×9 C=81 J.

• Answer: The work done is 81 Joules.

b) Find the electric current:

• Given: Charge (Q) = 3 C, Time (t) = 3 seconds.

• Formula: I=Q/t

• Calculation: I=3 C/3 s=1 A.

• Answer: The electric current is 1 Ampere.

V. Answer the following question : (1 x 4 = 4)

11. a) What is overload?

• Overloading of an electric circuit occurs when the total current drawn by the appliances connected to it exceeds the safe limit that the circuit wires can handle.

• Causes for overloading in a domestic electric circuit:

1. Connecting too many electrical appliances to a single socket.

2. Using a single power strip for multiple high-power appliances at the same time.

3. A sudden surge in the supply voltage.

4. A short circuit.

b) Function of an earth wire:

• The earth wire is a safety feature connected to the metallic casing of electrical appliances. Its main function is to prevent electric shocks.

• In case of a fault where the live wire touches the metal casing, the earth wire provides a low-resistance path for the current to flow to the ground. This causes a sudden increase in current in the circuit, which blows the fuse or trips the circuit breaker, thus cutting off the power supply and protecting the user from an electric shock.

VI. Answer the following question: (1 x 5 = 5)

12. a) What is electric power?

• Electric power is the rate at which electrical energy is transferred or dissipated in an electric circuit. It measures how quickly work is done by an electric current.

• SI unit: The SI unit of electric power is the watt (W).

• Three formulae to calculate electric power:

1. P=V×I (Power = Voltage × Current)

2. P=I2R (Power = Current² × Resistance)

3. P=RV2 (Power = Voltage² / Resistance)

b) Function of a fuse:

A fuse is a safety device used to protect electrical circuits and appliances from high currents due to overloading or short-circuiting. It contains a wire with a very low melting point. When the current exceeds a predetermined safe limit, the fuse wire melts and breaks the circuit, stopping the flow of current and preventing damage to the appliances.

Difference between filament wire and fuse wire melting points:

• The wire used in the filament of a bulb has a very high melting point (e.g., tungsten) because it needs to glow at a high temperature without melting to produce light.

• The wire used in a fuse has a very low melting point (e.g., an alloy of lead and tin) because its primary function is to melt and break the circuit when an overcurrent occurs.

13. Among the following reactions, a chemical reaction that resembles the reaction in which a reddish-brown coat is formed on the shining surface of iron articles is
(B) Formation of silver sulphide on silver articles by oxidation.
Explanation: The reddish-brown coat on iron is rust, which is formed through a process called rusting, a type of oxidation. Similarly, the blackening of silver is due to the formation of silver sulfide, which is also an oxidation reaction. Both are examples of corrosion.

14. The pH value of a solution is 7. The pH value of this solution can be increased by adding
(C) a small amount of sodium hydroxide.
Explanation: A pH of 7 indicates a neutral solution (like pure water). To increase the pH, you must make the solution more basic or alkaline. Sodium hydroxide (NaOH) is a strong base, so adding a small amount will increase the pH above 7.

15. An acid present in the stinging hairs of nettle leaves is
(A) Methanoic acid.
Explanation: The stinging sensation from nettle leaves is caused by the injection of methanoic acid (also known as formic acid) into the skin.

Answer the following questions:

16. Suggest any two methods to prevent rancidity.

• Method 1: Adding antioxidants to food items. Antioxidants are substances that prevent oxidation, thus stopping fats and oils from becoming rancid.

• Method 2: Storing food in airtight containers. This prevents oxygen from coming into contact with the food, thereby slowing down the oxidation process. Other methods include flushing with nitrogen gas and refrigeration.

17. When sodium sulphate solution is added to barium chloride solution, a white precipitate will be formed. Which are the ions responsible for this precipitate formation?
Answer: The ions responsible for the white precipitate formation are barium ions (Ba2+) and sulphate ions (SO42−). They combine to form a precipitate of barium sulphate (BaSO4).

18. Observe the below depicted experiments. Predict the nature of the salts that form in beaker A and beaker B.
Answer:

• Beaker A: The beaker contains a reaction between a weak acid and a weak base. The salt formed would be a salt of a weak acid and a weak base. The solution's pH will be close to 7, but it can be slightly acidic, basic, or neutral depending on the relative strength of the acid and base.

• Beaker B: The beaker contains a reaction between a strong acid and a weak base. The salt formed would be a salt of a strong acid and a weak base. This type of salt will hydrolyze in water to produce an acidic solution, so the pH will be less than 7.

19. List the observations that help us to determine that a chemical reaction has taken place.
Answer: The following observations indicate that a chemical reaction has occurred:

• Change in state: A gas is produced or a liquid turns into a solid.

• Change in color: The color of the reaction mixture changes.

• Evolution of gas: Bubbles are released.

• Formation of a precipitate: A solid forms from a clear solution.

• Change in temperature: The reaction mixture either becomes warmer (exothermic) or colder (endothermic).

20. Draw a diagram of the apparatus used in the electrolysis of water and label the following parts:
i) Graphite rod
ii) Oxygen
Answer:
A labeled diagram for the electrolysis of water includes a container (Hoffmann voltameter) filled with water, two electrodes (anode and cathode), and a power source.

• The graphite rods serve as the electrodes (anode and cathode).

• Oxygen gas is collected at the anode (the positive electrode).

21. Explanation: The diagram should show a conical flask with a thistle funnel and a delivery tube connected to a gas jar. Zinc granules are placed in the flask, and dilute sulphuric acid is added through the thistle funnel. The hydrogen gas produced passes through the delivery tube and is collected by the downward displacement of water in the gas jar.

22. i) Identify the exothermic and the endothermic reactions among these reactions.

• Exothermic: The reaction where water is added to calcium oxide. This is a highly exothermic reaction, releasing a significant amount of heat.

• Endothermic: The reaction where ferrous sulphate crystals are heated. This reaction absorbs heat from the surroundings to decompose the crystals.

ii) Reason: The green colour of ferrous sulphate (FeSO4) crystals disappears because they lose water of crystallization upon heating, forming anhydrous ferrous sulphate, which is white.

Type of reaction: This is a decomposition reaction. The ferrous sulphate decomposes into ferric oxide (Fe2O3), sulphur dioxide (SO2), and sulphur trioxide (SO3).

23. Write the molecular formula and any one use of each of the following salt:

i) Bleaching powder

• Molecular Formula: CaOCl2

• Use: Used as a bleaching agent in the textile and paper industries. It is also used for disinfecting drinking water.

ii) Plaster of Paris

• Molecular Formula: CaSO4⋅21H2O

• Use: Used by doctors for setting fractured bones. It is also used for making toys and decorative materials.

iii) Sodium carbonate

• Molecular Formula: Na2CO3

• Use: Used in the manufacture of glass, soap, and paper. It is also used as a cleaning agent for domestic purposes.

24. Strong Acid: A strong acid is an acid that ionizes completely in water to produce a large concentration of hydrogen ions (H+). Examples include hydrochloric acid (HCl) and sulphuric acid (H2SO4).

• Cause of Tooth Decay: Tooth decay is caused by the action of bacteria in the mouth. These bacteria produce acids by fermenting the sugar and food particles left in the mouth after eating. These acids corrode the tooth enamel, which is made of calcium phosphate, leading to tooth decay.

• Measure to Prevent: The most common measure is using toothpaste that contains a base (like sodium bicarbonate) to neutralize the acids produced by the bacteria. Brushing teeth after meals also helps to remove food particles and prevent the accumulation of plaque.

25. a) Difference: A concentrated acid has a higher percentage of acid dissolved in water, meaning a larger amount of acid and a smaller amount of water. A dilute acid has a lower percentage of acid dissolved in water, with a larger amount of water.

b) Detection using Litmus Paper:

• Acids: They turn blue litmus paper red.

• Bases: They turn red litmus paper blue.

OR

a) Differences:

1. Acids have a sour taste, while bases have a bitter taste.

2. Acids release H+ ions in an aqueous solution, while bases release OH− ions.

Detection of Basic Solution: A basic solution will cause no change in the colour of a blue litmus paper. It will remain blue. A red litmus paper, however, will turn blue in a basic solution.

b) Name any two products that are formed in the chlor-alkali process.

• Products: The main products of the chlor-alkali process are chlorine gas (Cl2) and sodium hydroxide (NaOH). Hydrogen gas (H2) is also produced as a byproduct.