Board Boosters
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 112 markseasy
Units and Measurements
Check whether the equation v = u + at is dimensionally consistent.
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[v] = L T^-1, [u] = L T^-1, and [at] = (L T^-2)(T) = L T^-1. Every term has the same dimension L T^-1, so the equation is dimensionally consistent (homogeneous).
[a] = L T^-2, [t] = T
Marking-scheme points
- ✓Write dimensions of each term
- ✓All three terms reduce to L T^-1
- ✓Same dimension on both sides => consistent
The concept
Every physically correct equation must have the same dimensions on both sides - a quick sanity check.
Why it matters
Physicists and engineers use it to catch mistakes and even guess formulas before solving anything.
💡 Memory trick
If the units don't match, the equation is scratch. Check L, M, T on both sides.
PhysicsClass 111 markeasy
Units and Measurements
How many significant figures are there in the measurement 0.00420 m?
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Three significant figures (4, 2 and the trailing 0). Leading zeros are not significant; a trailing zero after the decimal point is significant.
Marking-scheme points
- ✓Leading zeros: not significant
- ✓Trailing zero after decimal: significant
- ✓Answer = 3
The concept
Significant figures show how precisely a quantity was actually measured.
Why it matters
They stop you reporting false precision - vital in labs, medicine and engineering.
💡 Memory trick
Leading zeros DON'T count; trailing zeros after a decimal DO. So 0.00420 has 3.
PhysicsClass 113 marksmedium
Units and Measurements
Using Newton's law of gravitation, derive the dimensional formula of the universal gravitational constant G.
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From F = G M m / r^2, we get G = F r^2 / (M m). Dimensions: [G] = ([F][r^2]) / ([M][m]) = (M L T^-2 * L^2) / (M * M) = M^-1 L^3 T^-2.
G = F r^2 / (M m)
Marking-scheme points
- ✓Rearrange F = GMm/r^2 for G
- ✓Substitute [F] = M L T^-2
- ✓Final: [G] = M^-1 L^3 T^-2
PhysicsClass 113 markseasy
Motion in a Straight Line
A ball is thrown vertically upward with a speed of 20 m/s. Taking g = 10 m/s^2, find (a) the maximum height reached and (b) the total time before it returns to the thrower's hand.
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Motion in a Plane
A projectile is launched with speed u at an angle theta to the horizontal. Derive expressions for its time of flight, maximum height and horizontal range.
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Laws of Motion
Define impulse of a force and state its relation with momentum.
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Laws of Motion
A 2 kg block resting on a rough horizontal surface (coefficient of friction 0.2) is pulled by a horizontal force of 10 N. Taking g = 10 m/s^2, find its acceleration.
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Work, Energy and Power
State and explain the work-energy theorem.
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Work, Energy and Power
A body of mass 5 kg falls freely from a height of 20 m. Using g = 10 m/s^2, find its kinetic energy just before it strikes the ground.
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System of Particles and Rotational Motion
Define moment of inertia. State its SI unit and mention two factors on which it depends.
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System of Particles and Rotational Motion
State the theorem of parallel axes and use it to find the moment of inertia of a uniform rod (mass M, length L) about an axis through one end, perpendicular to the rod.
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Gravitation
Explain why the acceleration due to gravity decreases as we go to a height above the Earth's surface.
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Gravitation
Calculate the escape velocity from the surface of the Earth. Take g = 9.8 m/s^2 and R = 6.4 x 10^6 m.
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Mechanical Properties of Solids
Define Young's modulus of elasticity and give its SI unit.
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Mechanical Properties of Fluids
State Bernoulli's principle and write its mathematical form.
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Thermodynamics
State the first law of thermodynamics and give the sign convention used.
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Thermodynamics
Distinguish between an isothermal process and an adiabatic process (any three points).
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Thermodynamics
Describe the four steps of a Carnot cycle and write the expression for the efficiency of a Carnot engine.
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Kinetic Theory
Calculate the root-mean-square speed of oxygen molecules at 300 K. Take molar mass M = 32 g/mol = 0.032 kg/mol and R = 8.31 J/mol/K.
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Oscillations
Show that the oscillation of a simple pendulum is simple harmonic for small angles, and derive its time period.
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One question at a time is how every topper started. Bookmark this, revise a few each day, and watch the fear shrink. And if a friend is stressing about boards — send this their way. You both win.