 # Important 2 Marks Question Physics Class 12th

The Central Board of Secondary Education is one of the oldest and most preferred educational boards in India. The board conducts the final exam for 12th-standard students. Class 12 is considered as one of the most important stages of a student’s life. Students studying in class 12 should study hard to score good marks in their 12th standard board exam.

Physics is considered as one of the toughest subjects by many students. But if a student understands the concepts of Physics clearly, the subject can be easy and very interesting. With practice and little dedication, physics is one of the scoring subjects in CBSE class 12 board exams. Students are advised to focus on the important questions of Physics to score well in the exam.

The important 2 marks questions for physics class 12th are provided here so that students can prepare for their board exam more effectively. The questions are prepared by subject experts according to the latest CBSE exam pattern and syllabus. The important 2 marks questions given below will also make students familiar with the type of question and the difficulty level of the questions asked in the CBSE Class 12 board examination.

## Important 2 Marks Question Class 12th Physics

The Important 2 marks Question Physics Class 12th is provided here.

Question 1 – How are the electromagnetic waves produced? Draw a sketch of a plane e.m. wave propagating along the X-axis depicting the directions of the oscillating electric and magnetic field.

Question 2 – Calculate the shortest wavelength of light emitted in the Paschen series of the hydrogen spectrum. Which part of the electromagnetic spectrum, does it belong to? (Given: Rydberg constant, R = 1.1 x 107 m-1)

Question 3 – Depict the behaviour of magnetic field lines near
(i) Diamagnetic substance
(ii) Paramagnetic substance. Justify, giving reasons.

Question 4 – A charge q of mass m is moving with a velocity v, at right angles to the uniform magnetic field B. Deduce the expression for the radius of the circular path it describes.

Question 5 – A ray of light is incident on a glass prism of refractive index µ and refracting angle A. If it just suffers total internal reflection at the other face, obtain an expression relating the angle of incidence, angle of prism and critical angle.

Question 6 – A small illuminated bulb is at the bottom of a tank, containing a liquid of refractive µ up to a height H. Find the expression for the diameter of an opaque disc, floating symmetrically on the liquid surface in order to cut off the light from the bulb.

Question 7 – State the two points to distinguish between skywave and space wave modes of propagation.

Question 8 – Derive the Bohr’s quantization condition for the angular moment of the orbiting of an electron in a hydrogen atom, using de Broglie’s hypothesis.

Question 9 – State the two-point to distinguish between skywave and space wave modes of propagation.

Question 10 – (i) Write two characteristic features of nuclear force.

(ii) Draw a plot of the potential energy of a pair of nucleons as a function of their separation.

Question 11 – Electrons are emitted from the cathode of a photocell of negligible work function when photons of wavelength λ are incident on it. Derive the expression for the de Broglie wavelength of the electrons emitted in terms of the wavelength of the incident light.

Question 12 – (i) Define the refractive index of a medium.

(ii) In the following ray diagram, calculate the speed of light in the liquid of an unknown refractive index. Question 13 – A nucleus with mass number A = 240 and BE/A = 7.6 MeV breaks into two fragments each of A = 120 with BE/A = 8.5 MeV. Calculate the released energy.

Question 14 – State Brewster’s law. The value of the Brewster’s angle for a transparent medium is different for the light of different colours. Give reason.

Question 15 – Plot a graph showing the variation of de-Broglie wavelength

$$\begin{array}{l}\lambda \, versus \, \frac{1}{\sqrt{V}}\end{array}$$
, where V is accelerating potential for two particles A and B carrying the same charge but of m, m2 (m1 > m2). Which of the two represent a particle of smaller mass and why?

Question 16 – Two cells of EMFs 1.5 V and 2.0 V having internal resistances 0.2 Ω and 0.3 Ω respectively are connected in parallel. Calculate the emf and internal resistance of the equivalent cell.

Question 17 – Explain the terms
(i) Attenuation and
(ii) Demodulation used in the communication system.

Question 18 – Distinguish between ‘Intrinsic’ and ‘extrinsic’ semiconductors.

Question 19 – Show that the radius of nth orbit in hydrogen atom varies as n2, where n is the principal quantum number of the orbit.

Question 20 -The susceptibility of a magnetic material is -1.6 x 10-5. Identify the type of magnetic material and write its two properties.

Question 21 -Write the function of
(i) Transmitter and
(ii) The transducer in the context of the communication system.

Question 22 -A slab of dielectric constant K has the same area as the plates of a parallel plate capacitor but has thickness d/2, where d is the separation between the plates. Find the expression for the capacitance when the slab is inserted between the plates of the capacitor.