QUESTION PAPER
2024 BOARD EXAM
CBSE CLASS 12-PCB PHYSICS Board Paper 2024 — Set 2
2024
PHYSICS
CLASS 12-PCB
CBSE EXAMINATION PAPER-2024
PHYSICS
(Solved)
General Instructions :
Read the following instructions carefully and follow them :
- This question paper contains 21 questions. All questions are compulsory.
- This question paper is divided into 4 sections.
- Section A – questions number 1 to 12 are multiple choice questions
- Section B – questions number 13 to 15 are very short answer
- Section C – questions number 16 to 19 are short answer
- Section D – questions number 20 to 21 are long answer
- There is no overall choice given in the question paper. However, an internal choice has been provided in few questions.
- Use of calculator is NOT allowed.
Section A
Electrons drift with speed v_d in a conductor with potential difference V across its ends. If V is reduced to V/2, their drift speed will become:
A wire of length 4·4 m is bent around in the shape of a circular loop and carries a current of 1.0 A. The magnetic moment of the loop will be:
Which of the following quantity/quantities remains same in primary and secondary coils of an ideal transformer?
Current, Voltage, Power, Magnetic flux
A resistor and an ideal inductor are connected in series to a 100√2 V, 50 Hz ac source. When a voltmeter is connected across the resistor or the inductor, it shows the same reading. The reading of the voltmeter is:
An alpha particle approaches a gold nucleus in the Geiger-Marsden experiment with kinetic energy K. It momentarily stops at a distance d from the nucleus and reverses its direction. Then d is proportional to:
Assertion (A): Photoelectric current increases with an increase in intensity of incident radiation, for a given frequency of incident radiation and the accelerating potential.
Reason (R): Increase in the intensity of incident radiation results in an increase in the number of photoelectrons emitted per second and hence an increase in the photocurrent.
Assertion (A): Lenz's law is a consequence of the law of conservation of energy.
Reason (R): There is no power loss in an ideal inductor.
Assertion (A): The magnifying power of a compound microscope is negative.
Reason (R): The final image formed is erect with respect to the object.
Section B
What is the effect on the interference pattern in Young's double-slit experiment when (i) the source slit is moved closer to the plane of the slits, and (ii) the separation between the two slits is increased ? Justify your answers.
Section C
Two long, straight, parallel conductors carry steady currents in opposite directions. Explain the nature of the force of interaction between them. Obtain an expression for the magnitude of the force between the two conductors. Hence define one ampere.
The de Broglie wavelength λ as a function of 1/√K, for two particles of masses m₁ and m₂ are shown in the figure. Here, K is the energy of the moving particles.
(a) What does the slope of a line represent ?
(b) Which of the two particles is heavier ?
(c) Is this graph also valid for a photon ?
Justify your answer in each case.
Section D
(i) Give any two differences between the interference pattern obtained in Young's double-slit experiment and a diffraction pattern due to a single slit.
(ii) Draw an intensity distribution graph in case of a double-slit interference pattern.
(iii) In Young's double-slit experiment using monochromatic light of wavelength λ , the intensity of light at a point on the screen, where path difference is λ , is K units. Find the intensity of light at a point on the screen where the path difference is λ/6.
(i) Draw a labelled ray diagram of a compound microscope showing image formation at least distance of distinct vision. Derive an expression for its magnifying power.
(ii) A telescope consists of two lenses of focal length 100 cm and 5 cm. Find the magnifying power when the final image is formed at infinity.
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