Applied Physics Viva
Applied Physics Viva
Applied Physics Viva
2
Q8.Value of g at surface of earth is 9.81 m/sec , how g will varies with height and depth of earth?
A8. Its value decreases .
Q10 .Does time period of a pendulum depend upon the mass of bob?
A10. No.
Title of practical: To determine Youngs modulus of elasticity of the material of given wire Using Searles
apparatus.
Q1.What is elasticity?
A1. The property of the body by virtue of which it tends to regain its original configuration when external deforming forces
acting on it are removed.
Q3.What is strain?
A3. Strain caused in a body is defined as the ratio of change in a dimension of the body to the original dimension of the
body
Q5.What happens if a metal wire is loaded even beyond its elastic limit?
A5 Beyond elastic limit
(I) the elongation of wire is not directly proportional to the load
(ii) the wire does not regain its original state completely even on removal of the load.
Q7 Why?
A7 So that for a given load elongation is more and we may be able to measure its precisely.
Q9.Why is a fixed weight suspended from the compensating wire of Searles apparatus?
A9. A fixed weight is suspended from the lower end of compensating wire frame so as to keep the wire in taut poison.
Q1.What is viscosity?
A1 aproperty of fluids due to which they oppose relative motion between adjacent fluid layers.
Q2.What is the direction of viscous force?
A2Tangential to the surface but opposite to the direction of relative motion.
Q3. what is coefficient of viscosity?
A3. It is a constant for fluid and is a measure of its viscosity property.
Q4.State Stokes law.
A4. For a small spherical body of radius r falling down a liquid of coefficient of viscosity , a viscous force acts whose
magnitude is F= 6 r v.
Q5.What is terminal velocity?
Ans.It is maximum constant velocity with which a small spherical body may fall feely trough a fluid.
Q6.On What factor terminal velocity depend?
Ans. Terminal velocity is directly proportional to the square of the radius of falling body and inversely proportional to the
coefficient of viscosity of fluid.
Q7.Do air or gases also posses the property of viscosity?
Ans. Yes, But coefficient of viscosity of gases is less than liuid.
Q8.Which is more viscous water or glycerine?
Ans . Glycerine.
Q9.What is coefficient of viscosity?
Ans.It is constant for fluid and it is measure of its viscosity property.
Q10.How does the coefficient of viscosity of a liquid change with change I temperature?
Ans. Coefficient of viscosity of a liquid rapidly decreases with increase in its temperatu
Title of the practical: To determine refractive index of the material
of prism using graph.
Q1. What is refractive index ?
Ans. When a ray of light travels from one medium to the other medium then ratio of angle of incidence to the sine of angle
of refraction is always constant and it is called refractive index of the second medium with respect to the first medium.
Q2.on what factors the refractive index depends?
Ans. (i) Nature of the pair of media.
Q1. What is lens and how many types of lenses do you know?
A1. Lens is a transparent medium which is surrounded by one spherical and other plane or both spherical surfaces.
Lenses are manly of two types:
(i)convex
(II) Concave.
Subdivided Convex lens: (i) Plano-convex (ii) Double convex (III) Concavo-convex.
Concave lens: (i) Plano-concave (ii) double-concave (III) Convexo-Concave.
Q2. What is focal length of a lens?
A2. The distance between the optical centre of the lens and its focus is called focal length.
Q3. On what factors does the focal length of a lens depend?
A3. Focal length depends upon:
Radii of curvature of the surfaces.
(i)Refractive index of the medium of lens.
(ii)Colour of rays and
(iii)Media of surroundings.
Q4. What is meant by second focus of a lens?
A4. Light rays incident on lens, parallel to its principal axis, after refraction through the lens, passes through a point or
appears to diverge from a point, this point is called the second focus.
Q5. What will be the focal length of lens of refractive index 1.5 in water?
A5. It will be 4 times of its focal length in air.
Q6. When do you get the virtual image by a convex lens?
A6. When the object is placed between the optical centre and focus.
Q7.If an object is placed at the focus of a lens where will its image form?
A7. It will formed at infinity.
Q8.What is optical centre of lens?
A8. Optical centre of a lens is that point on its principal axis where from the ray passes through undeviated.
Q9. What is difference between a convex and a Concave lens?
A9. A Convex lens is thick in its middle portion and goes on becoming thin towards its ends whereas a concave lens is
thin in its middle portion and becomes thick towards its both ends.
Q10. Can you determine the focal length of concave lens by u-v or two pin methods?
A10. No, Because a concave lens always gives virtual image
Title of practical: To determine mechanical equivalent of heat by using Joules colorimeter
Q1.What is rate of cooling of body?
A1. Rate of cooling of a body means rate of loss heat by it.
Q2.Who gave the law of cooling?
A2.Newton.
Q3. State Newtons law of cooling.
A3. The rate of loss of heat by a hot body is directly proportional to the temperature difference between the hot body and
the surroundings. provided that the temperature difference is small.
Q4.What do you mean by small temperature difference?
A4.the temperature between the hot body and surroundings must be less than40 degree Centigrade
Q5.In your experiment why do you make the outer surface of calorimeter to be dull black?
A5.So that it becomes a good radiator of heat.
Q6.Why do you fill water in double walled enclosure?
A6.As specific heat capacity of water is very high. Its temperature practically remains constant in spite of the fact that is
receiving heat emitted by calorimeter.Q7.Why do you stir the hot water continuously?
A7.So that temperature of water remains uniform through out.
Q8.What is the limitation of Newtons law of cooling?
A8.It is true only when temperature difference between the hot body and the surroundings is small .for large temperature
difference the law fails.
Q9.What is radiation?
A9. Emission of thermal by any hot body, which can travel even through vacuum with a speed of 3x10 power 8meter per
second.
Q10.What is method of loss of heat for a body?
A10 A hot body may lose heat by conduction, convection or radiation.
Title of practical:. To plot magnetic lines of force in N-N and N-S condition
Q1. Can two magnetic lines of force intersect each other? why?
A1 No, two lines of force never intersect each other . If they intersect each other , then at the point of intersection, two
tangents can be drawn and thus we have two directions of magnetic field at that point , which is impossible.
Q2. What is neutral point?
A2 The points where net magnetic field due to the bar magnet and horizontal component of earths magnetic field is zero
are called neutral points.
Q3. Why is the compass needle tapped gently at the neutral point?
A3. Because, near the neutral point the field acting on the needle is very weak and not be able to overcome the force due
to friction at point of suspension.
Q4.What are the pole of a magnet?
A4 Poles of a magnet are the points where the magnetic property is maximum.
Q5.What is the poison of neutral points when North Pole of the magnet points toward geographic north or south?
A5. In this case, the neutral points are obtained on the equatorial line or broadside-on poison of the magnet for north.
In this case, the neutral points are obtained on the axial line or end side-on poison of the magnet for north.
Q6. What is magnetism?
A6. The Phenomenon of magnet attracting small piece of iron is known as magnetism.
Q7.What are the poles of a magnet?
A7. The poles are magnets are the points where the magnetic property is maximum.
Ans. A magnetic field that is constant both in magnitude and direction at every point is called uniform magnetic field.
Q.9.Why do way say that magnetic lines force are closed loops?
Ans. Because they start from N-pole of the magnet and enter at S-pole outside the magnet. wheres they move from S-
pole to N-pole inside the magnet.
Q.10.Can you have an isolated single pole?
Ans. No, poles of a magnet always occur in pairs