# CBSE 11TH PHYSICS - Online Test

Q1. The basic property of a fluid that makes it different from solids
Explaination / Solution:

fluids can flow due to unbalanced forces between the atoms of fluids.

Q2. Kinetic theory explains the behavior
Explaination / Solution:

The theory for ideal gases makes the following assumptions 1. Gases consist of particles in constant, random motion. They continue in a straight line until they collide with something—usually each other or the walls of their container. 2. Particles are point masses with no volume. The particles are so small compared to the space between them, that we do not consider their size in ideal gases. 3. No molecular forces are at work. This means that there is no attraction or repulsion between the particles. 4. Gas pressure is due to the molecules colliding with the walls of the container. All of these collisions are perfectly elastic, meaning that there is no change in energy of either the particles or the wall upon collision. No energy is lost or gained from collisions. 5. The time it takes to collide is negligible compared with the time between collisions. 6. The kinetic energy of a gas is a measure of its Kelvin temperature. Individual gas molecules have different speeds, but the temperature and kinetic energy of the gas refer to the average of these speeds. 7. The average kinetic energy of a gas particle is directly proportional to the temperature. An increase in temperature increases the speed in which the gas molecules move. 8. All gases at a given temperature have the same average kinetic energy. 9. Lighter gas molecules move faster than heavier molecules.

Q3. Heat is a form of
Explaination / Solution:

Heat is the amount of energy flowing from one body of matter to another spontaneously due to their temperature difference.

Q4. Physical quantities are
Explaination / Solution:

A physical quantity is a physical property of a phenomenon, body, or substance, that can be quantified by measurement.A physical quantity can be expressed as the combination of a magnitude expressed by a number – usually a real number – and a unit. All these given above can be expressed as explained so these are physical quantity.

Q5. The pendulum of a wall clock executes
Explaination / Solution:

It executes simple harmonic motion because in this motion restoring force is directly proportional to the displacement towards the mean position at any time.

Q6. According to Kepler’s Law of orbits:
Explaination / Solution:

The orbit of a planet around the Sun (or of a satellite around a planet) is not a perfect circle. It is an ellipse—a “flattened” circle. The Sun (or the centre of the planet) occupies one focus of the ellipse. A focus is one of the two internal points that help determine the shape of an ellipse. The distance from one focus to any point on the ellipse and then back to the second focus is always the same.

Q7. The position of an object moving in a straight line can be specified with reference to
Explaination / Solution:

To describe motion along a straight line, we can choose an axis, say X-axis, so that it coincides with the path of the object. We then measure the position of the object with reference to a conveniently chosen origin, say O, Positions to the right of O are taken as positive and to the left of O, as negative.

Q8. In wave propagation
Explaination / Solution:

because in wave propagation particles only moves in perodic motion, particles get collide with their neighbouring particles then transfer energy to them and comes back to their normal stage. Now next particle which gain energy get into excited state and starts moving periodically and get collide to next adjacent particle and so on. Thus in wave propagation particles only transfer their kinetic energy and momentum. Hence particles does not move therefore there is no flow of matter but there is movement of disturbance.

Q9. Rigid body is a body which
Explaination / Solution:

A rigid body is an idealization of a solid body in which deformation or change in shape is neglected on application of deforming force.

Q10. Physics is a
Explaination / Solution:

The natural sciences seek to understand how the world and universe around us works. There are five major branches (top left to bottom right): Chemistry, astronomy, earth science, physics, and biology.