# CBSE Class 11 Physics Solved Practice Paper 2017 2018: Set - II

CBSE Solved Paper for Class 11th Physics 2017 – 2018 final exam is available here for download in PDF format. You can download the completely solved paper with the help of download link given at the end of this article.

With the help of these CBSE Physics solved paper, students will get an idea about the level of questions which are frequently asked in CBSE school exams.

Most of the questions given in this 11^{th} Maths Solved Paper are based on important concepts of NCERT textbooks and previous year papers of different CBSE schools. These questions are very important for coming CBSE Class 11th Physics exam 2018. Time duration to solve this paper is 3 hours but students should try to solve this paper in less than 3 hours as this will enhance their writing speed.

**CBSE Class 11 Physics Syllabus 2017 - 2018**

**Some questions from Class 11 Physics Solved paper are given below:**

**Question:**

What is damped oscillations?

**Solution:**

When a simple harmonic system oscillates with decreasing amplitude with time, its oscillations are damped oscillation.

**Question:**

What is the Bulk modulus for a perfect rigid body?

**Solution:**

*K *= ‒(*pV*)/(Δ*V*)

**Question:**

State the condition under which the gravitational potential of a body will be zero?

**Solution:**

It is zero when there is an infinite separation between two interacting masses.

**Class 11th Physics NCERT Solutions**

**Question:**

Can we use Bernoulli’s equation to describe the flow of water through a rapid in a river?

**Solution:**

No, Bernoulli’s theorem is used only for stream line flow.

**Question:**

Is viscosity a vector quantity?

**Solution:**

No, viscosity is a scalar quantity.

**Question:** Write some assumptions made in the analysis of a projectile motion?

**Solution:**

The following assumptions are made while analyzing projectile motion:

(i) Air resistance is neglected

(ii) The acceleration due to gravity is assumed to be constant in magnitude and direction at all points of the motion of projectile.

(iii) The effect due to rotation of earth and curvature is neglected.

**Question:** What is the work done in blowing a soap bubble of radius *r *and surface tension S?

**Solution:**

Work done = surface tension × area of soap bubble

= S × (4πr^{2}) × 2 = 8SL.

**Question:** A meteorite burns in the atmosphere before coming to the earth’s surface. What happens to its momentum?

**Solution:**

The momentum of the meteorite is transferred to the air molecules. Thus momentum conservation principle is not violated.

**Question:** No external torque acts on a body, will its angular velocity remain conserved?

**Solution:**

Now torque is acting on a body ⇒ Net torque = 0.

Angular momentum, *L* = *I ω* = constant

Hence, angular velocity ω will remain constant as long as I remain constant i.e., if moment of inertia of the body about the given axis remains fixed.

**Question:** The spin angular velocity of a star is greatly enhanced when it collapses under gravitational pull and becomes a neutron star. Explain the reason?

**Solution:**

On collapsing under gravitational pull, the size of the star decreases. Therefore, its moment of inertia decreases. As angular momentum (L = I)* *is conserved, and I decreases, therefore, spin angular velocity increases.

**Question:** A block of mass 2 kg is placed on the floor. The coefficient of static friction is 0.4. A force F of 2.5 N is applied on the block horizontally in +X direaction. Calculate the force of friction between the block and the floor.

**Solution 12:**

Given, m = 2 kg, , F = 2.5 N

The limiting force of friction, f_{s} = *μ _{s }*R =

*μ*= 0.4 × 2 × 9.8 = 7.84 N.

_{s }mgAs, F < f_{s}

Hence, the block will not move. The value of static friction will be 2.5 N only.

**Question:** What is thermal conduction? Briefly explain the molecular mechanism of thermal conduction.

**Solution 13:**

Thermal conduction is the process in which heat is transmitted from one part of a body to another at a lower temperature through molecular collisions, without any actual flow of matter.

Molecular mechanism of thermal conduction: Let’s take an example of straight metal rod. When one end of a metal rod is heated, the molecules at the hot end vibrate with greater amplitude. So they have greater average kinetic energy. As these molecules collide with the neighbouring molecules of lesser kinetic energy, the energy is shared between them. The kinetic energy of the neighbouring molecules increases. This energy transfer takes place from one layer to the next, without the molecules leaving their average location. This way, heat is passed to the colder end of the rod.

**Download Completely Solved Class 11 Physics Paper in PDF format**