ISC Physics 2025 Question Paper with Answers
All 39 questions of the ISC Physics 2025 Question Paper, in printed order. Open a question to read it in full and see its answer.
- Q1(A)(i) When a battery is connected between the terminals P and Q, as shown in Figure 1 below, it is found that no current flows through… 1 mark · MCQ
- Q1(A)(ii) The relative permeability of substance ‘X’ is slightly less than one and that of substance ‘Y’ is slightly more than one. Then: 1 mark · MCQ
- Q1(A)(iii) If kinetic energy of moving electrons is made four times, then their de Broglie wavelength becomes: 1 mark · MCQ
- Q1(A)(iv) A student has made connections, as shown in Figure 2 below, so that the wires MN and ST repel each other. But it is observed that… 1 mark · MCQ
- Q1(A)(v) N-type semiconductor is that which has: 1 mark · MCQ
- Q1(A)(vi) When a convex lens made of glass is completely immersed in water, its focal length increases. 1 mark · Assertion-reason
- Q1(A)(vii) Diffraction of light is difficult to observe in everyday situations but can be observed in laboratory conditions. 1 mark · Assertion-reason
- Q1(B)(i) How does the resistance of a semiconductor crystal vary with its temperature? 1 mark · Short answer
- Q1(B)(ii) Figure 3 below shows an ideal transformer. Explain why current flowing through secondary coil is greater than that in primary… 1 mark · Short answer
- Q1(B)(iii) State any one difference between a primary rainbow and a secondary rainbow. 1 mark · Short answer
- Q1(B)(iv) Hubble telescope employs a large parabolic mirror as an objective. State any one advantage of using a mirror in place of a lens… 1 mark · Short answer
- Q1(B)(v) Name any one phenomenon where moving particles behave like waves. 1 mark · Short answer
- Q1(B)(vi) What is the minimum energy a gamma ray ($\gamma$) photon should possess to produce an electron - positron pair? 1 mark · Short answer
- Q1(B)(vii) In an energy band diagram of a certain material, forbidden band is absent. Identify this material. 1 mark · Short answer
- Q2(i) What is the effect on capacitance of a parallel plate capacitor if the distance between its plates is increased? How will… 2 marks · Short answer
- Q2(ii) Figures 4 and 5 represent the combination of two identical cells having negligible internal resistance. In which of the two… 2 marks · Short answer
- Q3 In case of a short electric dipole: What is the locus of a point having zero potential? If electric field intensity at a point in… 2 marks · Short answer
- Q4(i) Figure 6 below shows an electric circuit. Apply Kirchhoff’s laws to calculate: current ‘$I$’ flowing through the $2\ \Omega$… 2 marks · Numerical
- Q4(ii) In a potentiometer experiment, a cell of emf $1.25\text{ V}$ gives a balance point at $35\text{ cm}$ mark of the wire. If this… 2 marks · Numerical
- Q5 Magnetic field at the centre of a circular coil is $B$. Calculate the magnetic field at the same point when each of the current… 2 marks · Numerical
- Q6 The objective of a telescope consists of two lenses kept in contact. One lens has an optical power of $+2.0\text{ D}$ whereas the… 2 marks · Numerical
- Q7 Name the electromagnetic wave travelling from the satellite to the dish antenna shown in the image above. If the wavelength of an… 2 marks · Short answer
- Q8 With reference to photoelectric effect, define the terms: Threshold frequency. Work function. 2 marks · Short answer
- Q9 An infinite plane metallic sheet having surface charge density ‘$+\sigma$’ is placed in vacuum. P is a point at a small distance… 3 marks · Short answer
- Q10(i) Harry sets up a circuit as shown in Figure 7 below. He measures potential difference ‘$V$’ across the variable resistor R with an… 3 marks · Short answer
- Q10(ii) The graph below shows the variation of current density ($J$) with electric field ($E$) applied to two different metallic wires A… 3 marks · Short answer
- Q11 A galvanometer having a resistance of $20\ \Omega$ shows a full scale deflection with a current of $1\text{ mA}$. How can it be… 3 marks · Numerical
- Q12(i) Two infinitely long straight wires PQ and RS carrying currents $I_1$ and $I_2$ respectively are kept $10\text{ cm}$ apart in… 3 marks · Numerical
- Q12(ii) An electron and a proton are moving along the $+X$ axis. If an external magnetic field $B = 0.314\text{ T}$ is applied along $-Z$… 3 marks · Numerical
- Q13 A convex lens having small focal length is to be used as a magnifying glass (simple microscope) to obtain an image of a small… 3 marks · Short answer
- Q14 A parallel beam of light is travelling obliquely from an optically rarer medium to an optically denser medium. Draw a labelled… 3 marks · Short answer
- Q15 For any prism, show that refractive index ‘$n$’ of its material is given by… 3 marks · Derivation
- Q16 Two identical rectangular slits $5\text{ mm}$ apart are illuminated with a monochromatic light of wavelength $600\text{ nm}$. The… 3 marks · Numerical
- Q17 Plot a labelled graph of stopping potential ($V_s$) versus frequency ($\nu$) of incident UV radiation. State how the value of… 3 marks · Short answer
- Q18(i) Figure 9 shows a metallic rod MN of length $l = 3\text{ m}$ moving in an external uniform magnetic field… 5 marks · Numerical
- Q18(ii) An alternating emf $E = 5.0 \sin(314t)\text{ V}$ is applied to a circuit containing a resistor connected in series with an… 5 marks · Numerical
- Q19(i) Show that radius ($r_n$) of the $n^{\text{th}}$ Bohr orbit varies directly with square of the principal quantum number ($n$) of… 5 marks · Short answer
- Q19(ii) A group of students went on an educational tour of Bhabha Atomic Research Centre, Mumbai. They visited various nuclear reactors… 5 marks · Short answer
- Q20 When a television set (scientifically known as a television receiver) is opened, many components like semiconductor diodes… 5 marks · Short answer