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PHYSICS

1..in young?s double slit experiment the wavelength of lite was changed 4m 7000A to 3500A.while doubling the separation btw d slits which of the following is not true for this experiment?

a) the width of d fringes changes

b) color of brite fringes changes

c) the separation btw successive brite fringes chenges

d) the sep. btw successive dark fringes remains unchanged

2. A bird flies for with a velocity of |t-2| m/s in a straight line where t = time in seconds.It covers a distance of _______

a) 2m b) 4m c) 6m d) 8m

3. Four workers are sitting on the top four corners of a cubical room.These workers are trying to vertically lower a ceiling fan with the help of ropes. The workers are releasing the ropes with a constant speed v₀ each and the ceiling fan is coming down vertically along a line passing through the body centre of the room.At the instant the ceiling fan is passing through the body centre of the room,its speed is

a)v₀/3^1/2

b)v₀3^1/2

c)(v₀3^1/2)/2

d)2v₀/3^1/2

4. 1) two circular coils have their centred at the same point. the mutual inducatance between them will be maximum when their axes are:

a) perpendicular to each other

b) at 60 deg

c) at 45 deg to each other

d) parallel to each other

5. A coin is placed on a horizontal platform which undergoes vertical simple harmonic motion of angular frequency w. The amplitude of oscillation is gradually increased. The coin will leave the contact with the platform for the first time

(a) at the highest position of the platform.
(b) at the mean position of the platform.
(c) for an amplitude of g/w².
(d) for an amplitude of g²/w²

6. A cart of total mass M is at rest on a rough horizontal road. It ejects bullets at a rate of $\lambda\frac{kg}{s}$

kgs^-1 at an angle

with the horizontal. and at a velocity u(constant) relative to the cart. The coefficient of friction between the cart and the ground is

. Find the velocity of the cart as a function of t. The cart moves with sliding

a) (ucos?-

usin?)ln (M-?t)/M-µgt b)(ucos?-

usin?)ln M/(M-?t)-µgt c)(

cos?-usin?)ln M/(M-?t)-µgt d).none of d above

7. A uniform solid cube of mass M has edge length a. The moment of inertia of the cube about its edge diagonal will be
(a) (3)^1/2/ 2 Ma² (b) 1 / 2 Ma² (c) 5 / 12 Ma² (d) 7 / 12 Ma²

8. A block exerts a force of 9.8 N on a table. that table exerts a force of 10 N on the block .Assume g=9.8 m/s^2
then
a)the block exerts a force of 10 N on the table
b)the block exerts a force of 19.8 N on the table
c)the block exerts a force of 9.8 N on the table
d) the block has an upward acceleration

9. Magnifying power of a telescope can be increased by

a>inc.d length of telescope b>inc. fo c>inc.. diameter of obj. d>inc. fe

ASSERTION AND REASONING

(a) both A nd R r true nd R truly xplains A

(b) A nd R r true nd R does not xplain A

(c) A is true, R is false

(d) Ais false R is true

10. A: Terminal voltage of a cell is > e.m.f of cell during charging of d cell.

R:the emf of a cell is always gr8er than its terminal voltage

11. A: When a sample of a radioactive element with half life 15 days is kept for 30 days, the number of atoms left undecayed is 75%.

R: N/No = (1)^t/T, where the symbols have their usual meaning.

2

12. A. Two metals A and B have work function 2eV and 4eV. Metal A has lower threshold of wavelength for photoelectric effect.

R: work function = hv_o = hc/threshold wavelength.

13. A. Two unscrew a rusted nut we need a wrench with longer arm.

R: otherwise it will not open.

LINKED PARAGRAPH QUESTIONS:

The gravitational potential difference between the surface of a planet and a point 100 meters above its surface is 10 joules/kg.

14. If the gravitational field over this range is uniform, then the work done to raise the body of 5 kg from the surface to a height 40 meter is

a) 10 J b) 20 J c) 40 J d) 80 J

15. What will be the intensity of the field at the midpoint of the line joining the bodies?

a) 26 microN/kg b) 0.26 microN/kg c) 0.026 microN/kg d) 0.0026 microN/kg

16. In a gravitational field, if a body is bound then the total energy has:

a) positive value b)negative value c) zero value d) KE < PE

A simple pendulum attached to the roof of a lift has a time period of two seconds in a stationary lift.

17) If the lift is allowed to fall freely the frequency of oscillations of pendulum will be:

a) 0 b) 2hz c) 0.5 hz d) infinity

18.) A man measures the period of a simple pendulum inside the above lift and finds it to be T seconds and the left accelerates upwards with an acceleration of g/4, then the period of pendulum will be;

a) 2 T sqrt (5) b) T c) 2T/sqrt (5) d) T/4

19). If the period in the above lift is sqrt(5) sec, what will be the time period when the lift moves upwards with an acceleration of g/4

a) 2 b) ^]

(5) c) 2 *

5 d) {2 + sqrt (5)}

matrix match

20) column 1 column 2

1. faraday?s law of induction p) ind. E =L di/dt

2. newton?s second law q) i=dq/dt

3. induced emf due 2 an inductor r) ind. E =d_o/dt

4. current in a circuit s) F_ext. =dp/dt

21). A parallel plate capacitor of capacity C_ois charged by a battery . After charging battery is disconnected , separation between the plates is reduced and a dielectric is filled between the plates. Column I represents a quantity and column II represents the effect of changes made to Capacitor.

Column I	Column II
(A) P.E stored by Capacitor (B) Potential difference between plates (C) Capacity of Capacitor (D) Charge on capacitor	(p) Increase (q) Decrease (r) remains same (s) may increase/decrease

22. Match the following (more than one and non-unique matches are possible). Answer will be considered only if all matches are correct:

a) K electron capture p)excess protons

b) positron emission q)x rays

c)crystallography r)gamma rays

d) electron-positron annihilation s)photons

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