ROLL NO. NAME CLASS & SECTION

CATION

APEEJAY COMMON ANNUAL EXAMINATION, 2018-19

· CLASS-XI

PHYSICS (042)

015 Time allowed: 3 hrs.

Maximum Marks: 70

General Instructions:

1. All questions are compulsory. There are 27 questions in all. This question paper has four sections: Section A, Section B, Section C and Section D.
2. Section A contains five questions of one mark each, Section B contains seven questions of two marks each, Section C contains twelve questions of three marks each, and Section D contains three questions of five marks each.

1. There is no overall choice. However, internal choices have been provided in two questions of one mark, two questions of two marks, four questions of three marks and three questions of five marks weightage. You have to attempt only one of the choices in such questions.

1. You may use the following values of physical constants wherever necessary.

<math>c = 3 \times 10^8 \text{ m/s}</math> <math>h = 6.63 \times 10^{-34} Js</math>

<math>e = 1.6 \times 10^{-19} \text{ C}</math>

<math>\mu_0 = 4 \Pi \times 10^{-7} \text{ TmA}^{-1}</math>

<math>1/4\Pi \in_0 = 9 \times 109 \text{ Nm}^2 \text{ C}^2</math>

m_e = 9'.1×10^-31 kg

mass of neutron = <math>1.675 \times 10^{-27}</math> kg mass of proton = <math>1.673 \times 10^{-27}</math> kg Avogadro's number = <math>6.023 \times 10^{23}</math> per gram mole Boltzmann constant = 1.38×10^-23 JK^-1

SECTION-A

1. The Earth moving round the Sun in a circular orbit is acted upon by a force, and hence work must be done on the Earth by this force. Do you agree with this statement?

P.T.O.

OR

Give two examples from your daily life where according to Physics work done is zero. (1)

1. Which of the following processes shown here is reversible? Name the other process. (1)

P В 0 V-- () v (b) (a) OR

Write the expression of workdown in an (i) adiabatic process (ii) isothermal process.

1. An object is dropped from the top of a tower. Draw its velocity-time graph and

displacement- time graph. (1)

1. Two lenses of same mass and same radius are given. One lens is convex and other is concave. Which one will have greater moment of inertia, when rotating about an axis

perpendicular to the plane and passing through the centre? (1)

1. Prove that range is same for projection angles <math>(45 + \alpha)</math> and <math>(45 - \alpha)</math>.

(1)

SECTION-B

1. Does the function <math>y = \sin \omega t + \cos \omega t</math> represent a periodic motion? What is the period of the motion?

OR What is the beat frequency when two tuning forks of frequency 200 Hz and 205 Hz are sounded together? Mention one application of beats. (2)

1. The velocity time relation of an electron starting from rest is given by <math>v = kt</math>, where <math>k = 2 \,\mathrm{m} / \mathrm{s}^2</math>. Calculate the distance travelled in 3 seconds. (2)
2. If the density p, acceleration due to gravity g and frequency v are the basic quantities, find the dimensions of force in terms of <math>\rho</math>, g and <math>\upsilon</math>.

OR Distinguish between terms precision and accuracy of a measurement with the help of an example. (2) (2)