## Class/Course - Class XI

### Subject - Physics

#### Total Number of Question/s - 6437

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• 1. Physical World - Quiz

1. Magnetic confinement of plasma is the basis of ________
a) fusion test reactor (Toka mak)
b) fission test reactor
c) both a and b
d) none of these

2. The basic principle of optical fibres is__________.
a) total internal reflection of light
b) total external reflection
c) total interior reflection
d) none of these

• 2. Units and Measurements - Quiz

1. What is the % error in measurement of (T) of a pendulum if maximum errors in the measurement of (l) and (g) are 2% & 4% respectively?
a) 6%
b) 4%
c) 3%
d) 5%

2. While measuring acceleration due to gravity by a simple pendulum , a student makes a positive error of 2% in the length of the pendulum and a positive error of 1% in the value of time period. His actual percentage error in the measurement of the value of g will be
a) 3%
b) 0%
c) 4%
d) 5%

• 3. Motion in a Straight Line - Quiz

1. A ball is thrown from the top of a tower in vertically upward direction. Velocity at a point h metre below the point of projection is twice of the velocity at a point h metre above the point of projection. Find the maximum height reached by the ball above of top of tower.
a) 2h
b) 3h
c) (5/3)h
d) (4/3)h

2. A particle slides from rest from the topmost point of a vertical circle of radius r along a smooth chord making an angle θ with the vertical. The time of descent is
a) Least for θ = 0
b) Maximum for θ = 0
c) Least for θ = 450
d) Independent of θ

• 4. Motion in a Plane - Quiz

1. A rubber ball is dropped from a height of 5 metre on a plane , where the acceleration due to gravity is not known. On bouncing it rises to a height of 1.8 metre. The ball loses its velocity on bouncing by a factor of
a) 16/25
b) 2/5
c) 3/5
d) 9/25

2. A fly wheel is making 300 rpm. Its angular velocity in radian per second is
a) 5
b) 5 π
c) 10 π
d) 15 π

• 5. Laws of Motion - Quiz

1. A ball rolling on ice with a velocity of 5.6 m/s stops after travelling 8 m. If g = 9.8 m/s2, coefficient of friction is:
a) 0.1
b) 0.2
c) 0.3
d) 0.4

2. A block is gently placed on a conveyor belt moving horizontally with constant speed. After t=4 s, the velocity of the block becomes equal to velocity of the belt. If the coefficient of friction between the block and the belt is μ = 0.2, then the velocity of the conveyor belt is
a) 8 m/s
b) 6 m/s
c) 4 m/s
d) 2 m/s

• 6. Work, Energy and Power - Quiz

1. A uniform chain of length L and mass M is lying on a smooth table and third of its length is hanging vertically down over the edge of the table. If g is acceleration due to gravity, the work required to pull the hanging part on to the table is
a) MgL
b) Mg L/3
c) Mg L/9
d) Mg L/18

2. When linear momentum of a body is increased by 10%, increase in K.E. of the body is_________.
a) 20%
b) 21%
c) Both a and b
d) None of these

• 7. System of Particles and Rotational Motion - Quiz

1. If a solid sphere of mass 1 kg and radius 0.1 m rolls without slipping at a uniform velocity of 1 ms-1 along a straight line on a horizontal floor, the kinetic energy of the sphere is
a) (2/5)J
b) 1 J
c) (7/10)J
d) (7/5)J

2. Moment of interia of a hollow cyclinder of mass M and radius R, about the axis of cylinder is
a) (1/2) MR2
b) MR2
c) (2/3)MR2
d) (2/5)MR2

• 8. Gravitation - Quiz

1. Two satellites of the same mass are launched in the same orbit around the earth so as to rotate opposite to each other. If they collide inelastically and stick together as wreckage, the total energy of the system just after collision is
a) $-\frac{2GMm}{r}$
b) $-\frac{GMm}{r}$
c) $\frac{GMm}{2r}$
d) $\frac{GMm}{4r}$

2. A particle of mass M is situated at the centre of a spherical shell of mass and radius a. The magnitude of the gravitational potential at a point situated at a/2 distance from the centre, will begravitational at a/2 distance from the centre, will beA person being a mass of 1kg from infinity to a point P.Initially the mass was at rest but it moves at a speed of 2ms-1as it reaches at P. The work done by the person on the mass is -3J. The potential at P isThe change in potential energy, when a body of mass m is raised to a height n R from earth`s surface is (R = radius of earth)Four particles each of mass m are placed at the certices of a square of side I. What is the potrential energy of the system?
a) 2GM/a
b) 3GM/a
c) 4GM/a
d) GM/a

• 9. Mechanical Properties of Solids - Quiz

1. A wire is suspended vertically from a rigid support. When loaded with a steel weight in air, the wire extends by 16cm. When the weight is completely immersed in water, the extension is reduced to 14cm. The relative density of the material of the weight is
a) 2 g/cm3
b) 6 g/cm3
c) 8g/cm3
d) 16 g/cm3

2. A spring is stretched by appyling a load to its free end. The strain produced in the spring is
a) Volumetric
b) Shear
c) Longitudinal and shear
d) Longitudinal

• 10. Mechanical Properties of Fluids - Quiz

1. Under isothermal condition two soap bubbles of radii r1 and r2 coalesce to form a single bubble of radius r. The external pressure is P0. The surface tension of the soap in terms of the given parameters is
a) (P0(r3 - r13 + r23) / 4(r21 + r2r2 - r2)
b) (P0(r3 _ r13 - r23) / 4(r12 + r222 - r2)
c) (P0(r3 - r13 - r23) / 4(r21 + r22 - r2)
d) (P0(r3 -r31 - r32 ) / (4(21 - r22 - r2)

2. If a ball of steel (density ρ = 7.8 g cm-3) attains a terminal velocity of 10 cm s-1 when falling in a tank of water (coefficient of viscosity ηwater = 8.5 x 10-4 Pa.s) then its terminal velocity in glycerine (ρ = 1.2 g cm-3, η = 13.2 Pa.s) would be nearly
a) 1.6 x 10-5 cm s-1
b) 6.25 x 10-4 cm s-1
c) 6.45 x 10-4 cm s-1
d) 1.5 x 10-5 cm s-1

• 11. Thermal Properties of Matter - Quiz

1. A sphere and a cube of same material and same total surface area are placed in the same evacuated space turn by turn after they are heated to the same temperature. Find the ratio of their initial rates of cooling in the enclosure.
a) $\sqrt{\frac{\pi}{6}} : 1$
b) $\sqrt{\frac{\pi}{3}} : 1$
c) $\frac{\pi}{\sqrt{6}} : 1$
d) $\frac{\pi}{\sqrt{3}} : 1$

2. A system receives heat continuously at the rate 10W. The temperature of the system becomes constant at 700C when the temperature of the surroundings is 300C. After the heater is switched off, the system cools from 500C to 49.90C in 1min. The heat capacity of the system is
a) 1000J/0C
b) 1500 J/0C
c) 3000 J/0C
d) None of these

• 12. Thermodynamics - Quiz

1. A gas is compressed at a constant pressure of 50Nm-2 from a volume of 10m3 to a volume of 4m3. Energy of 100J is then added to the gate by heating. Its internal energy is
a) increased by 400 J
b) increased by 200 J
c) increased by 100 J
d) decreased by 200 J

2. The P-V diagram of a gas undergoing a cyclic process ABCDA is shown in graph, fig. where P is in N/m2 and V is in cm3. Identify the incorrect statement

a) 0.4 J work is done by the gas from A to B
b) 0.2J of work is done on the gas from C to D
c) no work is done by the gas from B to C
d) work is done by the gas from D to A

• 13. Kinetic Theory - Quiz

1. Average straight distance covered between sucessive collisions of molecules is called __________
a) mean free path of molecules
b)
c) Both a and b
d) none of these

2. 1 mole of monoatomic and one mole of diatomic gas are mixed together. The value of Cv is
a) 2R
b) (3/2)R
c) r1/r2 = c1/c2 = √p2/p1)
d) R/2

• 14. Oscillations - Quiz

1. The fundamental frequency of vibration of a stretched string varies ____ as ____ of the strings . Provided _____ are constant.
a) diameter ; length , tension and density of material ; inversely
b) inversely ; diameter ; length , tension and density of material.
c) Both a and b
d) none of these

2. The tension in the string of a simple pendulum is
a) constant
b) maximum in the extreme position
c) zero in the mean position
d) none of these

• 15. Waves - Quiz

1. A 40 dB sound waves strikes an eardrum whose area is 10-6 m2. To receive a total energy of 1J, time received is (l0 = 10-2W/m2)
a) 10-8s
b) 1010m
c) 106s
d) 1014s

2. Two paticles P and Q are executing SHM across same straight line whose equations are given and yP = Asin(ωt+ф1 ) and yQ = A cos(omega;t+ф2). An observer . At t=0 observes the particle P at a distance A/√2 moving to the right from means position O while Q at √(3A/2) moving to the left from the position O as shown to the left from mean position O as shown in fig. Then ф21 (in rad) is equal to

a) 5π/6
b) 3π/4
c) 5π/2
d) 7π/12

• 16. Scalar and Vector - Quiz

1. Two point masses 1 and 2 move with uniform velocities $\vec{v}_{1}$ and $\vec{v}_{2}$, respectively. Their initial position vectors are $\vec{r}_{1}$ and $\vec{r}_{2}$, respectively . Which of the following should be satisfied for the collision of the point masses?
a) $\frac{\vec{r}_{1} - \vec{r}_{2}}{\left | \vec{r}_{2} - \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} - \vec{v}_{1} \right |}$
b) $\frac{\vec{r}_{2} - \vec{r}_{1}}{\left | \vec{r}_{2} - \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} - \vec{v}_{1} \right |}$
c) $\frac{\vec{r}_{2} - \vec{r}_{1}}{\left | \vec{r}_{2} + \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} + \vec{v}_{1} \right |}$
d) $\frac{\vec{r}_{2} + \vec{r}_{1}}{\left | \vec{r}_{2} + \vec{r}_{1} \right |}$ = $\frac{\vec{v}_{2} - \vec{v}_{1}}{\left | \vec{v}_{2} + \vec{v}_{1} \right |}$

2. If $\vec{b}$ = $3\hat{i}+ 4\hat{j}$ and $\vec{a}$ = $\hat{i}$ - $\hat{j}$, the vector having the same magnitude as that of $\vec{b}$ and parallel to $\vec{a}$ is
a) $\frac{5}{\sqrt{2}}\left (\hat{i} - \hat{j} \right )$
b) $\frac{5}{\sqrt{2}}\left (\hat{i}+ \hat{j} \right )$
c) $5\left (\hat{i} - \hat{j} \right )$
d) $5\left (\hat{i} + \hat{j} \right )$

• 17. Conservation of momentum and Collision - Quiz

1. A force exerts an impulse I on a particle changing its speed from initial velocity u to final velocity 2u. The applied force and the initial velocity are oppositely oriented along the same line. The work done by the force is
a) $\frac{3}{2}Iu$
b) $\frac{1}{2}Iu$
c) Iu
d) 2 Iu

2. A ball of mass m moving with speed u undergoes a head-on elastic collision with a ball of mass nm initially at rest. The fraction of the incident energy transferred to the second ball is
a) $\frac{n}{1+n}$
b) $\frac{n}{(1+n)^{2}}$
c) $\frac{2n}{(1+n)^{2}}$
d) $\frac{4n}{(1+n)^{2}}$

• 18. Rotational Dynamics - Quiz

1. A slender rod of mass M and length L rests on a horizontal frictionless surface. The rod is pivoted about one of its ends. The impulse of the force exerted on the rod by the pivot when the rod is struck by a blow of impulse J perpendicular to the rod at other end is
a) J
b) $\frac{J}{2}$
c) $\frac{J}{3}$
d) Information is insufficient

2. A conical pendulum consists of a mass M suspended from a strong sling of length l. The mass executes a circle of radius R in a horizontal plane with speed v. At time t, the mass is at position $R\hat{i}$ and has v$\hat{j}$ velocity. At time t, the angular momentum vector of mass M about the point from which the string passes on the ceiling is

a) $MvR\hat{k}$
b) $Mvl\hat{k}$
c) $Mvl\left [ \sqrt{\frac{l^{2}-R^{2}}{l}}\hat{i}+\frac{R}{l}\hat{k} \right ]$
d) $-Mvl\left [ \sqrt{\frac{l^{2}-R^{2}}{l}}\hat{i}+\frac{R}{l}\hat{k} \right ]$

• 19. Fluid Dynamics - Quiz

1. The tension in a string holding a solid block below the surface of a liquid (where ρliquid > ρblock) as in shown in the figure is T when the system is at rest.

Then what will be the tension in the string if the system has upward acceleration a?
a) $T\left ( 1-\frac{a}{g} \right )$
b) $T\left ( 1+\frac{a}{g} \right )$
c) $T\left ( \frac{a}{g}-1 \right )$
d) $\frac{a}{g}T$

2. A U-tube of base length l filled with the same volume of two liquids of densities ρ and 2ρ is moving with an acceleration a on the horizontal plane. If the height difference plane. If the height difference between the two surfaces (open to atmosphere) becomes zero, then the height h is given by

a) $\frac{a}{2g}l$
b) $\frac{3a}{2g}l$
c) $\frac{a}{g}l$
d) $\frac{2a}{3g}l$