# IIT JEE Physics Exam Quiz!

10 Questions | Total Attempts: 257  Settings  .

• 1.
If the ratio of specific heat of a gas at constant pressure to that at constant volume is γ, the change in internal energy of a mass of gas when the volume changes from V to 2V under constant pressure p is:
• A.

RI (γ-1)

• B.

PV

• C.

PV I (γ-1)

• D.

γρV I(γ-1)

• 2.
Two walls of thickness d1 and d2 and thermal conductivities k1 and k2 are in contact. In the steady-state, if the temperatures at the outer surfaces are T1 and T2, the temperature at the outer wall is:
• A.

(k1T1d2+ k2T2d1 ) / ( k1d2+ k2d1)

• B.

(k1T1+ k2d2 ) / ( d1+ d2)

• C.

[(k1d1+ k2d2 ) / (T1+ T2)] * T1T2

• D.

(k1d1T1+ k2d2T2 ) / ( k1d1+ k2d2)

• 3.
A particle of charge +q an Eî and uniform magnetic field Bk follows a trajectory from P to Q as shown in the figure. The velocities at P and Q are vî and -2vĵ. Which of the following statement(s) is/are correct?
• A.

E=(3/4) * (mv^2/qa)

• B.

Rate of work done by the electric field at P is (3/4) * (mv^3/a)

• C.

Rate of work done by the electric field at P is zero.

• D.

Rate of work done by both the fields at Q is zero.

• 4.
Two rods, one of aluminum and the other made of steel, having initial lengths l1 and l2 are connected together to form a single rod of length l1+l2. The coefficients of linear expansion for aluminum and steel are αa and αs respectively. If the length of each rod increases by the same amount when their temperatures are raised by tC, then find ratio l1/(l1+l2):
• A.

αs/ αa

• B.

αa/ αs

• C.

αs/( αa + αs)

• D.

αa/( αa + αs)

• 5.
What is the condition for a single process to be both Isothermal and Isobaric?
• A.

One must use an ideal gas

• B.

Such a process is impossible

• C.

A change of phase is essential

• D.

One may use any real gas such as N2.

• 6.
The ends of a stretched wire of length L are fixed at x=0 and x=L. In one experiment the displacement of the wire is y1 = A sin(πx/L) sinωt and energy are E1 and in another experiment, its displacement is y2 = A sin (2πx/L) sin2ωt and energy is E2. Then:
• A.

E1=E2

• B.

E2=2E1

• C.

E2=4E1

• D.

E2=16E1

• 7.
A 0.25Kg block oscillates on the end of the spring with a spring constant of 200 Newton/meter. If the oscillation is started by elongating the spring 0.15meter and giving the block a speed of 3.0 meters/second, then what is the maximum speed of the block?
• A.

0.13 m/s

• B.

0.18 m/s

• C.

3.7 m/s

• D.

5.2 m/s

• 8.
A double-slit experiment is performed with the light of wavelength 500 nm. A thin film of thickness 2 μm and refractive index 1.5 is introduced in the path of the upper beam. The location of the central maximum will:
• A.

Remain un-shifted.

• B.

Shift downwards by nearly two fringes.

• C.

Shift upward by nearly two fringes.

• D.

Shift downward by 10 fringes.

• 9.
A short linear object of length b lies along the axis of a concave mirror of focal length f at a distance u from the pole of the mirror. The size of the image is approximately equal to:
• A.

B*[(u – f) / f]½

• B.

B*[f /(u – f)] ½

• C.

B*[(u – f)/f]

• D.

B*[f / (u – f)]^2

• 10.
The size of the image of an object which is at infinity as formed by a convex lens of focal length 30 cm is 2 cm. If a concave lens of focal length 20 cm is placed between the convex lens and the image at a distance of 26 cm from the convex lens, calculate the new size of the image.
• A.

1.25 cm

• B.

2.5 cm

• C.

1.05 cm

• D.

2 cm

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