A convex lens of focal length 20 cm is used as a magnifying glass. If an object is placed 5 cm from the lens, what is the nature of the image?

The correct answer is B: Virtual, erect, magnified. When object is between lens and focus (u < f), a convex lens produces virtual, erect, magnified image

A transformer has 500 turns in primary and 100 turns in secondary coil. If primary voltage is 220V, what is the secondary voltage?

The correct answer is A: 44 V. Using transformer equation Vs/Vp = Ns/Np, we get Vs = 220 × (100/500) = 44 V

Which of the following is the primary pigment responsible for capturing light energy in photosynthesis?

The correct answer is A: Chlorophyll a. Chlorophyll a is the primary pigment that directly participates in the light reactions of photosynthesis and forms the reaction centre of both photosystems.

The pH of cell sap in plant cells typically ranges between:

The correct answer is B: 4-6. Plant cell sap is slightly acidic due to organic acids like malic acid and citric acid, maintaining pH between 4-6.

The pulling force that moves water upward in xylem vessels is primarily due to:

The correct answer is C: Transpirational pull (tension) in xylem. Cohesion-tension theory explains that water is pulled upward due to transpirational pull creating negative pressure in xylem.