Question 1

Q1. Which of the following reactions represents oxidation?

Accepted Answer

Option C: Addition of oxygen. Oxidation involves addition of oxygen or removal of hydrogen from a substance.

Question 2

Q2. The focal length of a plane mirror is:

Accepted Answer

Option A: Infinity. A plane mirror can be considered as part of a sphere with infinite radius, so its focal length is infinite.

Question 3

Q3. Which blood component helps in clotting of blood?

Accepted Answer

Option D: Platelets. Platelets help prevent excessive blood loss by forming clots at injury sites.

Question 4

Q4. Which of the following compounds is unsaturated?

Accepted Answer

Option C: Ethene. Unsaturated compounds contain double or triple bonds. Ethene has a double bond.

Question 5

Q5. Which process removes harmful nitrogenous wastes from the human body?

Accepted Answer

Option C: Excretion. Excretion removes toxic metabolic wastes like urea from the body.

Question 6

Q6. A student added dilute sulphuric acid to zinc granules and passed the evolved gas through soap solution. The bubbles produced burned with a pop sound. This confirms the gas is:

Accepted Answer

Option C: Hydrogen. Hydrogen gas burns with a characteristic pop sound, confirming its presence.

Question 7

Q7. A resistor of 8 Ω carries a current of 2 A. The potential difference across it is:

Accepted Answer

Option C: 16 V. Using Ohm's law: V = IR = 8 × 2 = 16 V

Question 8

Q8. A plant kept horizontally for several days bends upward. This response is due to:

Accepted Answer

Option B: Geotropism. Shoots grow upward against gravity, showing negative geotropism.

Question 9

Q9. Which of the following statements is correct about alloys?

Accepted Answer

Option B: They generally have improved properties. Alloys are mixtures of metals designed to improve strength, hardness, or corrosion resistance.

Question 10

Q10. The element with atomic number 17 has valency:

Accepted Answer

Option A: 1. Electronic configuration is 2,8,7. It needs one electron to complete octet, so valency is 1.

Question 11

Q11. Refrigerators use insulating materials in doors mainly to:

Accepted Answer

Option B: Prevent heat transfer from surroundings. Insulating materials reduce heat flow into the refrigerator, maintaining low temperature efficiently.

Question 12

Q12. Assertion (A): Rusting is faster in humid weather. Reason (R): Moisture helps iron react with oxygen.

Accepted Answer

Option A: Both A and R are true and R is correct explanation of A. Rusting requires both oxygen and moisture. Humid air provides moisture necessary for corrosion.

Question 13

Q13. Assertion (A): Convex lenses are called converging lenses. Reason (R): Convex lenses converge parallel rays to a point.

Accepted Answer

Option A: Both A and R are true and R is correct explanation of A. Convex lenses bend parallel rays inward so they meet at the principal focus.

Question 14

Q14. Case Study: A student performed electrolysis of water using acidified water and graphite electrodes. Gas collected at one electrode was double the volume collected at the other. The gas collected in larger amount was:

Accepted Answer

Option C: Hydrogen. Hydrogen and oxygen are produced in 2:1 ratio during electrolysis of water.

Question 15

Q15. Case Study: A farmer used excessive pesticides in crops for many years. Birds feeding on insects in that area gradually declined due to accumulation of harmful chemicals in their bodies. This phenomenon is called:

Accepted Answer

Option B: Biomagnification. Toxic chemicals accumulate progressively at higher trophic levels in food chains.

Question 16

Q16. A student claims that distilled water conducts electricity well. Which statement is correct?

Accepted Answer

Option C: Distilled water conducts poorly due to absence of ions. Pure distilled water lacks free ions needed for conduction. (Common conceptual trap)

Question 17

Q17. Why is copper commonly used for electrical wiring?

Accepted Answer

Option C: Good conductivity and ductility. Copper conducts electricity efficiently and can be drawn into thin wires easily.

Question 18

Q18. A concave lens always forms images that are:

Accepted Answer

Option B: Virtual and erect. Concave lenses always produce virtual, erect, and diminished images regardless of object position. (High-frequency concept)

Question 19

Q19. Which compound contains the functional group -COOH?

Accepted Answer

Option C: Ethanoic acid. The -COOH group is called carboxyl group and is present in carboxylic acids.

Question 20

Q20. A student connected three identical resistors in series. Compared to one resistor, the effective resistance becomes:

Accepted Answer

Option D: Three times. In series combination, resistances add directly. Three identical resistors produce triple resistance.

Mock Test 07 Performance Solutions

Detailed Question Analysis

Q1. Which of the following reactions represents oxidation?

Q2. The focal length of a plane mirror is:

Q3. Which blood component helps in clotting of blood?

Q4. Which of the following compounds is unsaturated?

Q5. Which process removes harmful nitrogenous wastes from the human body?

Q6. A student added dilute sulphuric acid to zinc granules and passed the evolved gas through soap solution. The bubbles produced burned with a pop sound. This confirms the gas is:

Q7. A resistor of 8 \(\Omega\) carries a current of \(2\,\mathrm{A}\). The potential difference across it is:

Q8. A plant kept horizontally for several days bends upward. This response is due to:

Q9. Which of the following statements is correct about alloys?

Q10. The element with atomic number 17 has valency:

Q11. Refrigerators use insulating materials in doors mainly to:

Q12. Assertion (A): Rusting is faster in humid weather. Reason (R): Moisture helps iron react with oxygen.

Q13. Assertion (A): Convex lenses are called converging lenses. Reason (R): Convex lenses converge parallel rays to a point.

Q14. Case Study: A student performed electrolysis of water using acidified water and graphite electrodes. Gas collected at one electrode was double the volume collected at the other. The gas collected in larger amount was:

Q15. Case Study: A farmer used excessive pesticides in crops for many years. Birds feeding on insects in that area gradually declined due to accumulation of harmful chemicals in their bodies. This phenomenon is called:

Q16. A student claims that distilled water conducts electricity well. Which statement is correct?

Q17. Why is copper commonly used for electrical wiring?

Q18. A concave lens always forms images that are:

Q19. Which compound contains the functional group -COOH?

Q20. A student connected three identical resistors in series. Compared to one resistor, the effective resistance becomes:

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Mock Test 07 Performance Solutions

Detailed Question Analysis

Q1. Which of the following reactions represents oxidation?

Q2. The focal length of a plane mirror is:

Q3. Which blood component helps in clotting of blood?

Q4. Which of the following compounds is unsaturated?

Q5. Which process removes harmful nitrogenous wastes from the human body?

Q6. A student added dilute sulphuric acid to zinc granules and passed the evolved gas through soap solution. The bubbles produced burned with a pop sound. This confirms the gas is:

Q7. A resistor of 8 \(\Omega\) carries a current of \(2\,\mathrm{A}\). The potential difference across it is:

Q8. A plant kept horizontally for several days bends upward. This response is due to:

Q9. Which of the following statements is correct about alloys?

Q10. The element with atomic number 17 has valency:

Q11. Refrigerators use insulating materials in doors mainly to:

Q12. Assertion (A): Rusting is faster in humid weather. Reason (R): Moisture helps iron react with oxygen.

Q13. Assertion (A): Convex lenses are called converging lenses. Reason (R): Convex lenses converge parallel rays to a point.

Q14. Case Study: A student performed electrolysis of water using acidified water and graphite electrodes. Gas collected at one electrode was double the volume collected at the other. The gas collected in larger amount was:

Q15. Case Study: A farmer used excessive pesticides in crops for many years. Birds feeding on insects in that area gradually declined due to accumulation of harmful chemicals in their bodies. This phenomenon is called:

Q16. A student claims that distilled water conducts electricity well. Which statement is correct?

Q17. Why is copper commonly used for electrical wiring?

Q18. A concave lens always forms images that are:

Q19. Which compound contains the functional group -COOH?

Q20. A student connected three identical resistors in series. Compared to one resistor, the effective resistance becomes:

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