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1A converging lens of focal length 20 cm forms a real image of a candle placed 30 cm from the lens. Where is the image formed?

A 15 cm on the same side B 60 cm on the opposite side C 40 cm on the opposite side D 20 cm on the same side

2A car moves in a circular track of radius 50 m with a constant speed of 10 m s⁻¹. What is its centripetal acceleration?

A 0.2 m s⁻² B 2 m s⁻² C 5 m s⁻² D 20 m s⁻²

3A block of wood floats with 1/4 of its volume submerged in water. What is the density of the wood relative to water?

A 0.25 ρwater B 0.5 ρwater C 0.75 ρwater D 1.0 ρwater

4Which region of the electromagnetic spectrum has the shortest wavelength?

A Infrared B Visible light C Ultraviolet D Gamma rays

5When a coil is rotated in a uniform magnetic field, the induced emf is maximum when:

A The plane of the coil is parallel to the field B The plane of the coil is perpendicular to the field C The coil is at 45° to the field D The coil is not moving

6In a domestic AC circuit, the voltage is 240 V rms and the current is 5 A rms. What is the apparent power?

A 480 VA B 1200 VA C 240 VA D 600 VA

7In a cathode‑ray tube, the rays are produced by:

A Positive ions moving towards the cathode B Electrons emitted from the cathode C Neutrons emitted from the anode D Protons emitted from the filament

8Which of the following statements about X‑rays is correct?

A They are produced by nuclear fusion B Their wavelength is longer than visible light C They are generated when high‑energy electrons decelerate in a target D They can be reflected by ordinary mirrors

9According to the photoelectric effect, increasing the frequency of incident light while keeping intensity constant will:

A Increase the kinetic energy of emitted electrons B Increase the number of emitted electrons C Decrease the stopping potential D Have no effect if frequency is below threshold

10A sample containing a mixture of two radioactive isotopes decays such that after 10 h the activity is halved. Which type of decay could give this observation?

A Alpha decay with half‑life 10 h B Beta decay with half‑life 20 h C Gamma decay with half‑life 5 h D Spontaneous fission with half‑life 10 h