ISC Class 12 Practice Test 2026

About the ISC Class 12 exam

The ISC - Class 12 (ISC Class 12) is a icse board examination administered in India. It is designed to assess candidates' knowledge and proficiency across 9 key subject areas including Physics, Chemistry, Mathematics, Biology. This exam is widely recognized as an essential benchmark for students and professionals.

Use short ISC Class 12 practice sets to identify topics to revisit. Choose a subject and difficulty, answer questions, then review the explanations. New accounts get 30 question credits; further new questions use paid credits. Retaking previously seen questions is free.

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ISC Class 12 — quick answers

ISC Class 12 at a glance

8 free ISC Class 12 practice questions (2026)

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1. A charge q is placed at the center of the open mouth of a cylindrical vessel of radius R and length L. The electric flux through the walls of the vessel is:

   • q / ε₀
   • q / (2ε₀)
   • 2q / ε₀
   • Zero
   Show answer & explanation

   Answer: B. q / (2ε₀)

   If we complete the cylinder symmetrically by adding an identical cylinder on the open side, the charge q becomes enclosed at the exact center of the combined closed cylinder. The total flux through this closed cylinder is q/ε₀. By symmetry, the flux through one-half (the walls of the original open vessel) is half of the total flux, which is q / (2ε₀).

   Topic: Physics · medium

2. A parallel plate capacitor is charged and then disconnected from the charging battery. If the plates are now pulled further apart using insulating handles, then:

   • the charge on the capacitor increases and voltage decreases.
   • the capacitance increases and potential energy decreases.
   • the voltage across the plates increases and charge remains constant.
   • both the charge and potential energy remain constant.
   Show answer & explanation

   Answer: C. the voltage across the plates increases and charge remains constant.

   Since the capacitor is disconnected from the battery, the charge Q must remain constant. As the distance 'd' between plates increases, capacitance C = (ε₀ * A) / d decreases. Since V = Q / C, a decrease in C results in an increase in the potential difference V across the plates.

   Topic: Physics · easy

3. A copper wire of non-uniform area of cross-section has a steady current flowing through it. Which of the following physical quantities remains constant along the length of the wire?

   • Drift speed of electrons
   • Electric current
   • Current density
   • Electric field
   Show answer & explanation

   Answer: B. Electric current

   According to the principle of conservation of charge, the rate of flow of charge (current) must be the same across every cross-section of a single conductor under steady-state conditions. Drift speed, current density, and electric field all depend on the cross-sectional area and will vary along the wire.

   Topic: Physics · easy

4. In a potentiometer experiment, the balancing length with a cell of emf E in the secondary circuit is 2.4 m. When a resistor of 5 Ω is connected in parallel with the cell, the balancing length reduces to 2.0 m. The internal resistance of the cell is:

   • 0.5 Ω
   • 1.0 Ω
   • 1.2 Ω
   • 2.5 Ω
   Show answer & explanation

   Answer: B. 1.0 Ω

   The internal resistance r of a cell is given by r = R * ((L1 / L2) - 1). Here, L1 = 2.4 m, L2 = 2.0 m, and R = 5 Ω. Substituting the values: r = 5 * ((2.4 / 2.0) - 1) = 5 * (1.2 - 1) = 5 * 0.2 = 1.0 Ω.

   Topic: Physics · medium

5. A proton and an alpha particle enter a uniform magnetic field perpendicularly with the same kinetic energy. The ratio of the radii of their circular paths (rp : rα) is:

   • 1 : 1
   • 1 : 2
   • 2 : 1
   • 1 : √2
   Show answer & explanation

   Answer: A. 1 : 1

   The radius of a circular path in a magnetic field is given by r = √(2 * m * K) / (q * B). For a proton, m_p = m and q_p = q. For an alpha particle, m_α = 4m and q_α = 2q. Since both have the same kinetic energy K and are in the same magnetic field B: r_p / r_α = (√(m) / q) / (√(4m) / 2q) = (√(m) / q) / (2√(m) / 2q) = 1. Therefore, the ratio is 1 : 1.

   Topic: Physics · medium

6. A specimen of magnetic material is placed in a sinusoidally varying magnetic field. The susceptibility of the material is found to be small and positive. When the temperature of this specimen is increased, its magnetic susceptibility:

   • remains unaffected.
   • increases.
   • decreases.
   • first decreases and then increases.
   Show answer & explanation

   Answer: C. decreases.

   A small and positive magnetic susceptibility indicates that the material is paramagnetic. According to Curie's Law, the magnetic susceptibility (χ) of a paramagnetic material is inversely proportional to its absolute temperature T (χ ∝ 1/T). Thus, increasing the temperature causes the susceptibility to decrease.

   Topic: Physics · easy

7. A metallic square loop of side L and resistance R moves with a uniform velocity v perpendicular to a uniform magnetic field B acting into the plane of the paper. If the loop is partially inside the magnetic field and moving out of it, the force required to keep the loop moving with constant velocity is:

   • B²L²v / R
   • BLv / R
   • B²L²v² / R
   • Zero
   Show answer & explanation

   Answer: A. B²L²v / R

   The motional EMF induced in the loop is e = B * L * v. The induced current in the loop is I = e / R = B * L * v / R. The magnetic force acting on the conductor opposing its motion is F = I * L * B = (B * L * v / R) * L * B = B² * L² * v / R. To maintain a constant velocity, an equal and opposite external force must be applied.

   Topic: Physics · hard

8. In a series LCR AC circuit, at resonance, the phase difference between the current and the source voltage is:

   • π/2 rad
   • π/4 rad
   • π rad
   • Zero
   Show answer & explanation

   Answer: D. Zero

   At resonance, the inductive reactance (X_L) equals the capacitive reactance (X_C). The impedance of the circuit becomes purely resistive (Z = R). Therefore, the phase angle φ = tan⁻¹((X_L - X_C)/R) = 0, meaning the voltage and current are in phase.

   Topic: Physics · easy

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ISC Class 12 Exam Subjects

Available practice subjects: Physics, Chemistry, Mathematics, Biology, Computer Science, English, Economics, Commerce, Accounts. Select a subject for focused preparation. Coverage is not a guarantee of the complete official syllabus.

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