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The questions your board exam loves to ask
800 most-asked Class 11 & 12 (+1 / +2) questions across Physics, Chemistry, Maths and Biology — each with a model answer and the exact marking-scheme points examiners reward. Revise smart, walk in calm.
PhysicsClass 113 markshard
Laws of Motion
Why are roads banked at curves? Write the expression for the ideal speed on a frictionless banked road of angle theta and radius r.
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Roads are banked at curves so that the horizontal component of the normal reaction provides the centripetal force needed to turn, reducing reliance on friction and the risk of skidding. On a frictionless banked road, the ideal (safe) speed is v = sqrt(r g tan(theta)).
v = sqrt(r g tan(theta))
Marking-scheme points
- ✓Banking supplies centripetal force via normal reaction
- ✓Reduces dependence on friction
- ✓v = sqrt(r g tan theta)
PhysicsClass 113 markshard
Mechanical Properties of Fluids
Write the expression for the terminal velocity of a small sphere falling through a viscous fluid and name the quantities.
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v_t = (2 r^2 (rho - sigma) g) / (9 eta), where r is the radius of the sphere, rho its density, sigma the density of the fluid, g the acceleration due to gravity and eta the coefficient of viscosity. It is obtained by balancing the weight against the buoyant force and the viscous (Stokes) drag.
v_t = 2 r^2 (rho - sigma) g / (9 eta)
Marking-scheme points
- ✓v_t = 2 r^2 (rho - sigma) g / (9 eta)
- ✓From weight = buoyancy + viscous drag
- ✓v_t proportional to r^2
PhysicsClass 113 marksmedium
Thermodynamics
What is a refrigerator in thermodynamic terms? Write the expression for its coefficient of performance.
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A refrigerator is a heat engine working in reverse: it uses external work W to extract heat Q_c from a cold body and reject a larger heat Q_h to the hot surroundings, so Q_h = Q_c + W. Its coefficient of performance is beta = Q_c / W = Q_c / (Q_h - Q_c). A good refrigerator has a high beta.
beta = Q_c / (Q_h - Q_c)
Marking-scheme points
- ✓Reverse heat engine, uses work W
- ✓Q_h = Q_c + W
- ✓beta = Q_c / W = Q_c/(Q_h - Q_c)
PhysicsClass 113 marksmedium
Oscillations
For a particle in SHM given by x = A sin(omega t), write the expressions for its velocity and acceleration, and state where each is maximum.
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Waves
Write Newton's formula for the speed of sound in a gas and state Laplace's correction to it.
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Laws of Motion
A person of mass 50 kg stands in a lift. Find the apparent weight when the lift accelerates upward at 2 m/s^2. Take g = 10 m/s^2.
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Work, Energy and Power
Write the condition (minimum speed) for a body to just complete a vertical circle of radius r at the highest point, and the corresponding minimum speed at the lowest point.
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Waves
Compare the harmonics produced in an open organ pipe and a closed organ pipe.
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Motion in a Straight Line
A body starts from rest and moves with a uniform acceleration of 2 m/s^2. Find the distance travelled by it during the 5th second.
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Electric Charges and Fields
Two point charges of 2 microcoulomb and 3 microcoulomb are placed 30 cm apart in air. Calculate the electrostatic force between them.
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Electric Charges and Fields
Calculate the electric field intensity at a point 30 cm from a point charge of 5 microcoulomb in air.
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Electric Charges and Fields
Define electric dipole moment. Derive the expression for the electric field at a point on the axial line of a short dipole.
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Electric Charges and Fields
State Gauss's law in electrostatics and write its mathematical form.
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Electric Charges and Fields
Using Gauss's law, derive the expression for the electric field due to an infinitely long straight uniformly charged wire.
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Electrostatic Potential and Capacitance
Calculate the electric potential at a point 9 cm away from a point charge of 4 microcoulomb in air.
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Electrostatic Potential and Capacitance
Derive the expression for the capacitance of a parallel plate capacitor with air between the plates.
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Electrostatic Potential and Capacitance
Three capacitors of 2 microfarad, 3 microfarad and 6 microfarad are connected first in series and then in parallel. Find the equivalent capacitance in each case.
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Current Electricity
What is drift velocity? Derive the relation between current and drift velocity.
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Current Electricity
Three resistors of 2 ohm, 3 ohm and 6 ohm are connected in parallel. Find their equivalent resistance. What would it be in series?
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Current Electricity
Draw (in words) and derive the balance condition of a Wheatstone bridge.
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