SSLC Physics Annual Exam Answer Key March 2026

🔬 SSLC PHYSICS · MARCH 2026

Total score: 40Answer key (English)Time: 1½ hrs

SECTION A (4 × 1 = 4)

1.Ohmic heating indicates

✔ answer

(c) Joule heating

2.Tuning fork on table — statement & reason

✔ answer

(c) The Statement is correct but the Reason is incorrect.

Explanation: Placing stem increases sound (forced vibration), but resonance requires equal frequencies, and frequency does not increase.

3.Rainbow — light inside water droplet

✔ answer

(d) (ii) and (iv) are correct (Internal reflection & refraction)

4.Matching: Bar magnet / Solenoid

✔ answer

(c) ABF and DEC
Bar magnet (A) → permanent magnetism (B), polarity cannot change (F).
Solenoid (D) → variable strength (E), polarity can change (C).

SECTION B (7 × 2 = 14)

5.Echo between buildings (0.2 s, 0.3 s; speed 340 m/s)

✔ answer

(a) Minimum 0.1 s delay / reflector at ≥ 17 m.
(b) Distance = 85 m (34 + 51)

6.Ray diagram: convex lens virtual image

✔ answer

Object between F and optical centre; rays diverge; virtual, erect, magnified on same side.

[Diagram: convex lens with object inside focus, dotted back-projections]

7. (A)Scattering experiment (sun/sky colour)

✔ answer

Experiment: Water + milk, light beam. Side view → blue scatter; end view → red. Explains blue sky & red sunrise/sunset.

8.Household wiring – earth & 3-pin socket

✔ answer

(a) X = Earth wire / grounding.
(b) [Diagram: Live → switch → socket (L); neutral direct to N; earth to E].

9.Wheel & axle (20000 N, R=50 cm, r=10 cm)

✔ answer

(a) MA = 5 (50/10).
(b) Increase wheel radius / decrease axle radius.

10. (A)Heater: 7.2 MJ in 2 h

✔ answer

(a) Electrical → heat energy.
(b) Power = 1000 W (7,200,000 J / 7200 s).

11.Rule for electricity & magnetism (left hand)

✔ answer

Fleming’s Left Hand Rule: thumb → force, forefinger → field, middle finger → current.

SECTION C (6 × 3 = 18)

12.Three coloured lights (RGB)

✔ answer

(a) A = Blue, D = Yellow.
(b) Primary: A (Blue), B (Green), C (Red).
(c) Complementary pair: C (Red) and D (Yellow).

13.Heating coil 200 V, 60 Ω, 5 min

✔ answer

(a) Alloy = Nichrome.
(b) Heat = 200 000 J (using V²/R · t).
(c) Lower R → heat increases (H ∝ 1/R at constant V).

14. (A)Lever – MA, principle, load arm

✔ answer

(a) Figure (c) (third-order) MA < 1.
(b) Effort × effort arm = load × load arm.
(c) Load arm = 0.5 m (1 m / 2).

15.Solenoid – polarity & field strength

✔ answer

Solenoid: long helical coil.
Statement incorrect: polarity depends on current direction (clock rule).
Increase field: more turns, higher current, or soft iron core.

16.Wave (C,R) & audibility

✔ answer

(a) Longitudinal wave.
(b) C = Compression, R = Rarefaction.
(c) f = 350 / 0.01 = 35 000 Hz → ultrasonic → inaudible.

17. (A)Concave lens: u=20 cm, f=10 cm

✔ answer

(a) v = -6.67 cm (20/3 cm, sign indicates virtual)
(b) Virtual, erect, diminished, same side as object.

SECTION D (4 scores)

18. (A)Mutual induction & transformer

✔ answer

(a) Bulb glows only at switch on/off because magnetic field changes; steady field induces no current.

(b) Replace battery with AC source → continuous changing field → mutual induction → bulb glows continuously.

(c) Voltage needed: V₁ = 200 V (N₁/N₂ = V₁/V₂ → 100/200 = V₁/400).

⚡ Note: For question 7, 10, 14, 17, 18 only one option is shown (the one selected in key). For OR parts, similar step-by-step answers are available.

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✅ SSLC March 2026 Physics – Complete answer key | prepared for evaluation