Easy & Concise NCERT Physics Ch-8,9,10: All Exercises Solved

Calculate Young's modulus from the given stress and strain, yielding 75,000 N/m^2, and identify yield strength at 300×10^6 N/m^2 where the material shifts from elastic to permanent deformation.

Determine the vertical deflection of the opposite face of an aluminium cube fixed to a wall, under a 100 kg load, using a 25 GPa shear modulus, giving 4×10^-7 m.

Calculate the compressional strain of a steel column using a Young's modulus of 210 GPa and a 125,000 N load across a cross-sectional area of 0.8478 m^2.

Compute the maximum load a steel cable can support by multiplying the maximum stress by the cross-sectional area, with radius 1.5 cm and stress 1e8 N/m^2, giving about 7.07e4 N.

Compute elongation of a 1 m steel wire carrying a 14.5 kg mass whirled at 2 rev/s in a circle, using stress, strain, and Young's modulus to obtain 1.97 mm.

Use bulk modulus to relate the 79 atm pressure change to strain in water, yielding a 3.638 x 10-3 strain and density about 1.033 x 10^3 kg per m3.

Compute the fractional change in volume of a glass slab under 10 atm pressure using the bulk modulus; the fractional change equals pressure divided by bulk modulus (37×10^9 N/m^2).

Apply bulk modulus to compute the pressure needed to compress water by 0.10%, confirming a bulk modulus of 2.2e9 Pa and a pressure of 2.2e6 Pa.

Explain why blood pressure is higher at the feet than the brain using hydrostatic principles and blood column height. Atmospheric pressure decreases with altitude; hydrostatic pressure is scalar.

Mercury forms a convex meniscus with glass due to strong mercury-mercury forces, yielding an obtuse contact angle; water forms a concave meniscus, yielding an acute angle and spreading.

Water wets glass because water-glass adhesion exceeds water-water cohesion, causing spreading. Mercury beads on glass because mercury-mercury forces dominate over mercury-glass adhesion.

Understand that surface tension is the force per unit length on an imaginary line across a liquid surface, independent of the surface area and governed by intermolecular forces.

Water with detergent lowers the contact angle, causing the liquid to spread on cloth and penetrate tiny pores, while stronger capillary rise (cosine of the contact angle) enhances cleaning efficiency.

See how a spinning cricket ball deviates from a parabolic trajectory due to the Magnus effect. A pressure difference between the ball's sides creates a sideways force, steering the ball.

Explore Torricelli's barometer with mercury and Pascal's wine experiment to compute a 10.5 m wine column from atmospheric pressure, using p = rho g h.

Apply the pressure equals force over area relation to a hydraulic automobile lift with a 3000 kg load and a 425 cm2 piston, yielding about 7.06e5 Pa.

Explain why absolute pressure is used in Bernoulli's equation, noting that absolute pressure equals gauge plus atmospheric pressure and that atmospheric pressure cancels when the same at all points.

Compute lift from net pressure on the wing, P1 minus P2, times wing area, using Bernoulli's principle, yielding about 1513 newtons.

Apply the continuity equation AV = constant to relate cross-sectional areas and velocities, then compute V2 from A1V1 = A2V2 with given areas and V1, yielding 0.636 m/s.

The film's surface tension supports a 0.045 N weight in all three figures, independent of U-frame shape, with only the slider's tension countering the weight.

Determine the excess pressure in a soap bubble (delta P = 4T/R) and an air bubble (2T/R), then add atmospheric and hydrostatic pressures to find the internal pressure.

Convert neon and carbon dioxide triple-point temperatures (24.57 k and 216.55 k) from kelvin to celsius and then to fahrenheit using kelvin minus 273.15 and 9/5 c plus 32.

Using the triple point of water at 273.16 Kelvin, relate temperature scales A and B by equating 200A with 350B and derive 7DA = 4TB.

The lecture derives alpha from resistance data using r = r0(1 + alpha (t - t0)) and then finds the temperature for 123.4 ohms, yielding 2.53 kelvin.

Learn to convert the triple point of water from 0.01 °C to 32.018 °F using the formula F = C × 1.8 + 32.

Apply the ideal gas equation PV = nRT to calculate temperature from pressure and moles, using hydrogen and oxygen data, and note non-ideal behavior at higher pressures, recommending lower pressures.

Compute the metal's specific heat from heat exchange with water and a calorimeter; result 432.8 J per kg per K, with losses causing the actual value to be higher.

Calculate the heat lost by the body from mass, specific heat, and temperature change. Determine the water evaporated and its rate, 4.3 grams per minute.

Compute the energy transferred to boil 6 kg of water using heat of vaporization, then solve for temperature T with thermal conductivity and area, yielding about 273.8 degrees Celsius.

Link reflectivity to emissivity by explaining that higher reflectivity reduces absorption, leading to lower emission; a glass slab illustrates more reflection, less absorption, and thus lower emissivity.

Brass tumbler feels colder than a wooden tray because metal conducts heat faster, so heat flows quickly from the hand into brass, while wood acts as an insulator.

Explain why an optical pyrometer calibrated to a blackbody underestimates red-hot iron in open air due to lower emission, and yields readings in a furnace because reflections raise detected radiation.

Absorbing heat from the Earth's surface, atmospheric gases warm the planet, while steam-based heating systems prove more efficient for warming buildings than hot-water systems.

Steam-based heating is more efficient than hot water because steam has higher heat content and releases latent heat during condensation, enabling faster, more uniform heating.

Apply Newton's law of cooling to model T(t)=Ts+(T0−Ts)e^(−kt). Solve from 80 to 50 in 5 minutes to find k, then compute 60 to 30 and obtain 600 seconds (10 minutes).