# Grade 11 Physics 2071 Pastpaper

## Physics

## Grade 11 , 2071

## Regular Examination Paper

**Full Marks : 100**

**Pass Marks : 35**

**Time : 03:00:00**

*Q.NO. 5 (a)*

What do you mean by the banking of a curved path? Derive an expression for the banking angle.

*Q.NO. 6 (c)*

Does cubical expansively depend upon the initial volume of a solid? Write the unit of this expansivity. Also derive its relation with superficial expansivity.

*Q.NO. 8 (a)*

What is the physical difference between electric potential are electric field intensity? Derive an expression for the potential differences between two points in the electrostatic field.

*Q.NO. 10 (b)*

The element of an electric fire with an output of 1.5 Kw is a cylinder of 0.3 m Iong and 0.04 m in radius. Calculate its temperature if it behaves as a black body.

*Set C Q.NO. 1 (a)*

How does the frequency of vibration of a simple pendulum related with its length? Hence estimate the frequency of a second's pendulum.

*Set C Q.NO. 1 (b)*

A force (in Newton) expressed in vector notation as F =( 2 î + ĵ - 3 K̂ ) is applied on a body so that the displacement produced in meter is given by D = ( i ̂ - 2 j ̂ - 3 k̂). Express the result and nature of the work done.** **

*Set C Q.NO. 1 (c)*

Express the dimension of the velocity gradient from the definition of the coefficient of viscosity.

*Set C Q.NO. 1 (d)*

In usual notation, a simple harmonic motion is given as y = a sin (wt - θ ). Find acceleration.

*Set C Q.NO. 1 (e)*

What is a black hole? Write down its characteristic features.

*Set C Q.NO. 1 (f)*

Explain the significance of the banking of a curved road.

*Set C Q.NO. 2 (a)*

What is the difference between a real and an ideal gas? Explain on the basis of the hypothesis of the kinetic theory.

*Set C Q.NO. 2 (b)*

Explain the significance of anomalous expansion of water with an example observed in nature.

*Set C Q.NO. 2 (c)*

Entropy is defined in the second law of thermodynamics. Can the first law be expressed in terms of entropy? How?

*Set C Q.NO. 3 (a)*

Spherical mirror may behave as a plane mirror as a special case. Explain.

*Set C Q.NO. 4 (a)*

Two positive charges separated by a distance create an electrostatic field Can i. electric potential, and {ii) electric field intensity be zero at a point between the charges? Justify your answer

*Set C Q.NO. 4 (b)*

Three capacitorsof the same capacitance are joined in (i) series, and (ii) all in parallel.By how much one of these combinations is larger in magnitude? Explain.

*Set C Q.NO. 5 (a)*

Define torque and couple in rotational motion. Derive an expression for the work done by the couple.

*Set C Q.NO. 5 (b)*

What do you understand by Poisson's ratio? Derive an expression for energy stored in a stretched wire.

*Set C Q.NO. 5 (c)*

Explain the concept of geostationary satellite. Find an expression for the total energy of the moon revolving around the earth

*Set C Q.NO. 5 (d)*

What is elastic collision? Prove that the colliding objects exchange their velocities in one dimensional elastic collision.

*Set C Q.NO. 6 (a)*

*Set C Q.NO. 6 (b)*

Define the coefficient of thermal conductivity, Describe, with necessary theory, an experiment for its determination in the laboratory.

*Set C Q.NO. 7 (b)*

How will you make difference between real and virtual images? Obtain an expression for the relation between object distance, image distance and the focal length in the case of a convex mirror.

*Set C Q.NO. 8 (a)*

State and explain Gauss law. Use it to find the electric field due to a charged conducting sphere (i) outside, and (ii) inside.

*Set C Q.NO. 8 (b)*

Define capacitance of a capacitor. Deduce an expression for the capacitance of a parallel plate capacitor.

*Set C Q.NO. 9 (a)*

A 650 KW power engine of a vehicle of mass 1.5 x 105 Kg is rising on an inclined plane of inclination 1 in 100 with a constant speed of 60 km/hr. Find the frictional force between the wheels of the vehicle and the plane.

*Set C Q.NO. 9 (b)*

A mass of 0.2 Kg is rotated by a string at a constant speed in a vertical circle of radius 1 m. If the minimum tension in the string is 3 N, calculate the magnitude of the speed and the maximum tension in the string.

*Set C Q.NO. 9 (c)*

Find the work done required breaking up a drop of water of radius 5 x 10-3 m into eight drops of water, assuming isothermal condition.

*Set C Q.NO. 9 (d)*

A bullet is fired with a velocity of 100 m/s from the ground at an angle of 60° with the horizontal. Calculate the horizontal range covered by the bullet. Also calculate the maximum height attained.

*Set C Q.NO. 10 (a)*

*Set C Q.NO. 10 (b)*

Air is compressed adiabatically to half of its volume. Calculate the change in its temperature.

*Set C Q.NO. 10 (c)*

A Carnot engine works between the source and the sink with efficiency 40%. How much temperature of the sink be lowered keeping the source temperature constant so that its efficiency increases by 10%?

*Set C Q.NO. 11*

What is the apparent position of an object below a rectangular glass slab of refractive index 1.45 and the thickness 0.06 m if a layer of water 0.05 m thick is on the top of the glass slab?

*Set D Q.NO. 1 (a)*

Explain the difference between a "push" and a "pull" in the case of a heavy roller on a level road where the force acts on the roller making an angle with the horizontal road.

*Set D Q.NO. 1 (b)*

A bomb is to be dropped from a moving helicopter on a target on the ground. Explain how it can hit the target.

*Set D Q.NO. 1 (c)*

A force (in Newton) expressed in vector notation as F = 4i + 7 ĵ - 3 k̂ is applied on a body and produces a displacement (in meter), D = 3î - 2ĵ - 5K̂ in 4 seconds. Estimate the power.

*Set D Q.NO. 1 (d)*

A student writes an expression of the force causing a body of mass (m) to move in a circular motion with a velocity (v) as F = mv^{2}. Use the dimensional method to check its correctness.

*Set D Q.NO. 1 (e)*

Explain the difference between a simple and conical pendulum.

*Set D Q.NO. 1 (f)*

A SHM is represented as y =a cos (wt+ ϕ) in usual notation. Find its acceleration.

*Set D Q.NO. 1 (g)*

What is a black hole? Write down its characteristic features.

*Set D Q.NO. 2*

Why are dews formed in the clear nights but not in the cloudy ones? Explain.

*Set D Q.NO. 2 (a)*

Define the coefficient of cubical expansion of a solid and hence write an expression for the variation of its density with temperature.

*Set D Q.NO. 2 (c)*

Explain the significant difference between the first and the second laws of thermodynamic.

*Set D Q.NO. 3 (a)*

Draw an outline sketch to show the chromatic aberration in the case of a lens. How can achromatism be achieved?

*Set D Q.NO. 3 (b)*

What do you understand by 1 lumen and 1 phot? What do they signify?

*Set D Q.NO. 4 (a)*

Explain the difference between a polar end a non-polar dielectrics with one example of each.

*Set D Q.NO. 4 (b)*

How can a neutral body be charged with negative electricity by induction? Explain.

*Set D Q.NO. 5*

Define Young's modulus, bulk modulus, modulus of rigidity and Poisson's ratio.

*Set D Q.NO. 5 (c)*

Describe the experimental method to find the coefficient of viscosity of a liquid by Stoke's method.

*Set D Q.NO. 5 (d)*

What do you mean by a rigid body? Obtain an expression for the moment of inertia of a thin and uniform rod about an axis passing through the centre and perpendicular to its length.

*Set D Q.NO. 6 (a)*

Describe in brief the method of mixture to determine the specific heat of a solid in the laboratory?

*Set D Q.NO. 6 (b)*

Derive the ideal gas equation on the basis of theory of kinetic theory of gases.

*Set D Q.NO. 6 (b)*

What is perfect gas? Prove that the average kinetic energy of a gas molecule is directly proportional to the absolute temperature of the gas.

*Set D Q.NO. 6 (c)*

What is an adiabatic process? Prove the relation Pvγ= constant, where notations carry usual meanings.** **

*Set D Q.NO. 7 (a)*

Sketch an outline diagram of an astronomical telescope and derive expression for its angular magnification when the final image is formed at the least distant of distinct vision.

*Set D Q.NO. 8 (b)*

State and explain Gauss law of electrostatics and apply it to find electric field intensity on the surface and inside the surface of a charged sphere.

*Set D Q.NO. 9 (a)*

A capillary tube of 0.3 m diameter is placed vertically inside a liquid of density 800 Kg -3, surface tension 5 x 10 -4 Nm-1 and angle of contact 30°. Calculate the height to which the liquid rises in the capillary tube.

*Set D Q.NO. 9 (b)*

A stationary mass explodes into two parts of mass 4 kg and 40 kg. The initial kinetic energy of larger mass is 10 J. Find the velocity of the smaller mass.

*Set D Q.NO. 9 (c)*

At what angle should a circular road be banked so that a car running at 50 Km/hr be safe to go round the circular turn of 200 m radius?

*Set D Q.NO. 9 (d)*

An earth satellite moves in a circular orbit with a speed of 6.2 kms-1. Find the time of one revolution and its centripetal acceleration.

*Set D Q.NO. 10 (a)*

A Carnot engine works between "the source and the sink with 25% efficiency. How much temperature of the source be raised keeping the sink at the same constant temperature at 27°C so that the efficiency is increased by 15 %?

*Set D Q.NO. 10 (c)*

From what height should a block of ice be dropped in order that it may melt completely?

*Set D Q.NO. 11*

At what position an object is placed in front of a concave mirror of radius of curvature 0.4 m so that an erect image of magnification 3 is produced?

*Set D Q.NO. 12*

Two spheres of radii 5 cm and 10 cm are given charges 100C and 50 C respectively and wire. Calculate the loss of energy after connection.

*Set D Q.NO. 12 (or)*

Three capacitors of 1μ f, 2μf and 3μf .The same capacitors are again connect in parallel. Compare their equivalent capacitance. Which one of these combinations gives larger value of capacitance?