KVPY 2017 NEWS

NATIONAL LEVEL ONLINE/OFFLINE TEST

# KVPY 2017 Interview: Physics Questions

Last Updated - May 22, 2017

KVPY (Kishore Vaigyanik Protsahan Yojana) is the ongoing initiative of Government of India, for school students, which aims to encourage students to pursue courses in basic science and develop a research aptitude in the field. The selection for this prestigious fellowship is considered after two rounds.

Over years’ everyday phenomenon find explanation in Physics. The application of this science is engraved in our lives. Understanding of physics solves enough day-to-day problems. It is only fitting that this subject is part of prestigious KVPY scholarship. Here, we discuss some questions related to Physics.

#### Ques. State the process of conversion of energy from one form to another. Can heat energy be converted to electric energy?

Ans. The conversion of energy from one form to another is the result of law of conservation of energy which states that, “Energy can neither be created nor be destroyed but only be changed from one form to other.” Yes, Thermoelectric Generator converts heat energy to electric energy using the phenomenon of “Seeback Effect”.

#### Ques. What principle does desert cooler uses to cool the room during summer? How it is related to humidity?

Ans. Desert cooler cools through the evaporation of water by exploiting large enthalpy of vaporization of water. It is similar to the cooling mechanism of our body. The evaporation of water drops the temperature thereby providing cool environment. Desert cooler works better on dry day. If humidity is high the evaporation will not be so prevalent since, atmosphere already has moisture content.

Check KVPY Result

#### Ques. What is heat? What is the difference between heat and energy?

Ans. Heat is a measurement of energy. Any material is composed of molecules which in turn has some amount of energy. Every molecule by virtue of its vibration has some kinetic energy. Heat is the measure of combined total energy of all the molecules.

#### Ques. Explain is difference between heat and temperature?

Ans. Just as heat is the measure of energy, temperature is the measure of heat.

#### Ques. Explain the term pressure. How is it different from force and stress?

Ans. Pressure is defined as force per unit area applied to an object in a direction perpendicular to the surface. On the other hand, stress is the intrinsic property of the body under load/pressure and is related to the internal forces. Stress can be defined as a reaction produced by the molecules of the body under some external action which may produce some deformation to the natural state of body. While pressure is the result of applied force, stress is the result of pressure.

#### Ques. Explain reflection and refraction with their effects along with examples for each.

Ans. Both reflection and refraction is observed when light travels from one medium to another. If light traveling from one medium to another after striking the surface of other medium returns back to first medium, then it is reflection. Mirror reflects light. If the light traveling from one medium to another to another, after striking the surface of second medium continues traveling in the second medium with changed speed and direction it is refraction. Light traveling from air to water refracts in water.

Also Check KVPY 2017 Interview: Maths Questions

#### Ques. What is sound? Does frequency is associated with only sound waves?

Ans. Sound is the audible vibration which travels through a medium. No frequency is associated with other waves as well. Ex. EM waves.

#### Ques. Why Sky appears to be blue in day and black in night but leaves always appear to be green?

Ans. Color of anything can be attributed to the color being reflected or radiated by that object. In the day, the sunlight is received and atmosphere absorbs other colors while radiating blue. In the night, no light is received. The absence of color makes night dark. Similar explanation follows for leaves, where chlorophyll reflects just green color.

#### Ques. Which type of mirrors do we use commonly in our home?

Ans. Plane mirror, Concave mirror, Convex Mirror.

#### Ques. What is specific gravity? Can it be less than 1?

Ans. Specific gravity is the ratio of density of a substance to the density of water. Of course, it can be less than 1. For fluids like oil, specific gravity is less than 1.

#### Ques. Give one example of electromagnetic wave.

Ans.

• Visible light
• UV rays
• Infrared Rays

Ans.   390-700

#### Ques. Explain the relation between charge and current? If you carry a charge with you does it means current is flowing?

Ans. Charge is the property of matter due to which a matter experiences force when exposed to electromagnetic field.

Current is the flow of these charges enabled by carriers such as ions or electrons.

No. It will be static.

#### Ques. Define the unit of any quantity.

Ans. A unit of measurement is a definite smallest magnitude of any quantity. It is defined and adopted by convention or by law, and is used as a standard for measurement of the same quantity.

#### Ques. How images are formed in our eye?

Ans. An image is formed in the human eye due to the particular arrangement of the stimulated cells. Light passes through the pupil, is refracted by the lens and is absorbed by pigment cells in the retina, altering the pigments and triggering neurons to fire. This stimulates the cells to arrange and form an image.

#### Ques. Define friction force. What happens when the friction force is varied by applying the external force?

Ans.Friction is the force opposing and resisting the relative motion of two solid objects. It is usually proportional to the force which presses the surfaces together as well as the roughness of the surfaces. Friction force varies with the applied external force until maximum frictional force is reached. Once external force surpasses that limit, the relative motion takes place.

#### Ques. A tiger is 1km away from you. What will be the time taken by him to eat you up, approximately? The friction of the ground surface is zero.

Ans. Friction force is imperative for a living being to move. Without friction tiger won’t be able to move.

Ans. Yes

#### Ques. What are contact forces?

Ans. Contact forces are the forces which act at the point of contact between two objects.

#### Ques. Forces are “due to an interaction between two bodies” Explain the statement.

Ans. This statement can be attributed to the Newton’s law of motion. Think carefully on all the three laws.

#### Ques. Define Potential energy. How is potential energy generated? From which source?

Ans. Potential energy is energy possessed by a body by virtue of its position relative to others, stresses within it, electric charge, and other factors. There are different types of potential energies. Gravitational potential is generated due to mass of the object. Elastic potential energy is generated by the stresses caused due to deformation. Potential Energy is attributed to the state of body itself.

#### Ques. Give 3 examples of a simple machine.

Ans.  Inclined plane

Wedge

Screw

Pulley

#### Ques. How scissors are made workable? What concept is applied behind making it?

Ans. Scissors are first class of lever.  The force you apply is on the opposite side of the fulcrum to the force you produce. The cutting force of the scissors works on the law of lever. The force applied on the blade can be calculated by length of the handle and force applied on the grip of handle. A pair of scissors is an example of two first class levers connected together at the fulcrum.

#### Ques. What is direction of acceleration in circular motion, linear motion and random motion?

Ans. The direction of acceleration is perpendicular to the motion of body in circular motion. The direction of acceleration is parallel to the motion of body in linear motion. If vibration is considered as random motion then, direction of acceleration changes direction constantly (at fixed interval of time in case of vibration).

×

## Related News & Articles

2017-06-03 18:12:25KVPY 2017

### KVPY 2018 Results

KVPY 2018 Results will be declared in the first we ...

2017-08-14 16:37:14KVPY 2017

### KVPY Merit List 2017

2017-07-14 17:08:54KVPY 2017

### KVPY 2018 Application Form

KVPY 2018 Application Form will be available from ...

2017-06-02 14:27:15KVPY 2017