1 Atoms and Nuclei
In terms of Rydberg constant R, the shortest wavelength in Balmer series of hydrogen atom spectrum will have wavelength:
(1) 3/2 R (2) 9/4 R (3) 1/R (4) 4/R
2 Physical world and measurement
The dimensional formula for latent heat is:
1.M0L2 T-2 2.M2 L0 T-2 3.M2 L-2 T0 4.M0 L-2 T2
3 Electrostatics
The electric field in a region of space is given by $$\vec{E}=(\hat{5i}+\hat{2j} )Nc^{-1}$$ . The electric flux due to this field through an area $$2m^{2}$$ lying in the Y-Z plane in S.I. units is
1) 2√29 2) 20 3) 10√2 4) 10
As $$2m^{2}$$ area is in y-z plane its area vector which is perpendicular to y-z plane is in x axis. $$\therefore$$ area vector $$=2(\hat{i})$$ given $$E=5i+2j$$ We know flux $$\phi=E.A$$ $$=(2i).(5i+2j)$$ $$\phi=10$$
4 Wave Optics
Two slits in Young's experiment have widths in the ratio 1 : 25. The ratio of intensity at the maxima and minima in the interference pattern, $$\displaystyle \frac{I_{max}}{I_{min}}$$ is
1) $$\displaystyle \frac{4}{9}$$ 2) $$\displaystyle \frac{9}{4}$$ 3) $$\displaystyle \frac{121}{49}$$ 4) $$\displaystyle \frac{49}{121}$$
Intensity is proportional to width of the slit. thus, $$\dfrac{I_1}{I_2}=\dfrac{1}{25}$$ or $$\dfrac{a_1}{a_2}=\sqrt{\dfrac{I_1}{I_2}}=\dfrac{1}{5}$$ or $$a_2=5a_1$$ now, $$\dfrac{I_{max}}{I_{min}}=\dfrac{(a_1+a_2)}{(a_1-a_2)^2}=\dfrac{(a_1+5a_1)^2}{(a_1-5a_2)^2}=36/16=9/4$$
5 Electrostatics
Four charges q1=1μC, q2=2μC, q3=3μC and q4=4μC are placed at (0,0,0), (1m,0,0), (0,1m,0), (0,0,1m) respectively. Let $$\vec { { F }_{ i } } $$ be the net force acting on $$i$$th charge of the given charges then $$\sum { \vec { { F }_{ i } } } =$$
1) 0.018 2) 0.02N 3) 0.036N 4) zero
6 Motion of System of Particles and Rigid Body
A ball is whirled around in a horizontal circle at constant speed v by a string of length r. How much work is done by the string tension T during one complete revolution?
1. Zero
2. T·(2pr)
3. T·v
4. T· pr2
7 Work Energy and Power
A block of wood is pulled along a horizontal bench at a constant speed of 15 m/s by a force of 8N. How much work is done against friction in 6 seconds? (1) 720J (2) 120J (3) 48J (4) 20J
8 Gravitation
Satellite is moving around the Earth in a circular orbit with a velocity V. If the gravitational force of the Earth were to suddenly disappear, then the satellite would 1) move with a velocity V, tangentially to its circular orbit. 2) fall towards the surface of the Earth. 3) move radially outwards with a velocity V. 4) spirally move away from the Earth.
The satellite is held in orbit because of two forces. One is the gravitational force and the second is the centrifugal force. When the gravitational force disappears, there is no force to hold it in orbit. So it moves in the direction of its velocity, which is tangential to the circular path it was describing earlier.
9 Gravitation
A satellite orbits at a height h above the Earth's surface. Let R be the Earth's radius. If Ve is the escape velocity and Vo is the orbital velocity of the satellite orbiting at a height h << R, then 1) Vo2 = 2 Ve2 2) Ve2 = 2 Vo2 3) Ve = 2 Vo 4) Ve = Vo
10 Thermodynamics
Figure shows the volume (V) vs Temperature (T) graphs for certain amount of perfect gas at two pressure P1 and P2 Then. 1) P1=P2 2) P1 > P2 3) P1 < P2 4) P1 ≥ P2
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