CBSE Questions for Class 11 Medical Physics Work, Energy And Power Quiz 1 - MCQExams.com

A vibrating body possesses:
  • electrical energy
  • nuclear energy
  • potential energy
  • sound energy
A force $$\vec { F } =\left( { 3x }^{ 2 }+2x-7 \right) $$ N acts on a 2 kg body as a result of which the body gest displaced x=0 to x=5 cm. The work done by the force will be-
  • 35 Joule
  • 70 Joule
  • 115 Joule
  • 270 Joule
A particle moves along the x-axis from x=0 to x=5 m under the influence of a force given by $$F=\left( { 7-2x+3x }^{ 2 } \right) N.$$ The work done in the process is
  • 70 J
  • 270 J
  • 35 J
  • 135 J
A uniform elastic string has length $$a_{1}$$ when tension is $$T_{1}$$ and length $$a_{2}$$ when tension is $$T_{2}$$. The amount of work done in stretching it from its natural length to a length $$(a_{1}+ a_{2})$$ is ?
  • $$\dfrac {1}{2}\dfrac {(a_{1}T_{1}+a_{2}T_{2})^{2}}{2(T_{1}-T_{2})(a_{1}- a_{2})}$$
  • $$\dfrac {1}{2}\dfrac {(a_{1}T_{1}-a_{2}T_{2})^{2}}{2(T_{1}-T_{2})(a_{1}- a_{2})}$$
  • $$\dfrac {1}{2}\dfrac {(T_{1}+T_{2})^{2}}{2(T_{1}-T_{2})(a_{1}- a_{2})}$$
  • $$\dfrac {1}{2}\dfrac {(T_{1}+ T_{2})}{2(T_{1}-T_{2})(a_{1}- a_{2})}$$
Velocity-time graph of a particle of mass 2 kg moving in a straight line is as shown in figure. Work done by all the forces on the particle during the motion is:
1392827_e49dbb3dfa6a4ecc918b83069c161981.JPG
  • $$400 J$$
  • $$-400 J$$
  • $$-200 J$$
  • $$200 J$$
A particle is displaced from a position $$(2\hat { i } -\hat { j } +\hat { k } )$$ metre to another position $$(3\hat { i } +2\hat { j } -2\hat { k } )$$ meter under the action of force $$(2\hat { i } +\hat { j } -\hat { k } )$$ N. Work done by the force is:
  • 8 J
  • 10 J
  • 12 J
  • 36 J
A balloon with its contents weighing 160 N is moving down with an acceleration of g/2 $${ ms }^{ -2 }$$ the mass to be removed from it so that the balloon moves up with an acceleration of g/3$${ ms }^{ -2 }$$ is 
  • 5 kg
  • 10 kg
  • 6 kg
  • 3 kg
In $$10 s$$, a body of $$6 kg$$ mass is dragged $$8 m$$ with uniform velocity across a floor by a steady force of $$20 N$$. The K.E of the body is:
  • $$2.92 J$$
  • $$0.92 J$$
  • $$1.92 J$$
  • $$0J$$
A body of mass 5 Kg initially at rest is moved by a horizontal force of 2 N on a smooth horizontal surface. The work done by the force in 10 s is
  • 20 J
  • 30 J
  • 40 J
  • 60 J
A force of $$ \left(4 x^{2}+3 x\right)  $$ N acts on a particle which displaces it from $$  x=2 m  $$ to $$  x=3 \mathrm{m}  $$.
The work done by the force is
  • $$32.8 J$$
  • $$3.28 J$$
  • $$0.328 J$$
  • zero
A body of mass m is rotating in a vertical circle of radius 'r' with critical speed. The difference in its K.E. at the top and the bottom is _____.
  • 2mgr
  • 4 mgr
  • 6 mgr
  • 3 mgr
If the sum of all the forces acting on a particle is zero, then
  • it will necessarily be in equilibrium.
  • then it will not be in equilibrium.
  • then it mat or may not be in equilibrium.
  • none of these
A stone is projected from a horizontal plane. It attains maximum height $$H$$ and strikes a stationary smooth wall and falls on the ground vertically below the maximum height. Assume the collision to be elastic the height of the point on the wall where ball will strike is:
  • $$H/2$$
  • $$H/4$$
  • $$3H/4$$
  • none of these
State whether the given statement is True or False :
The energy of an object that is due to the object's motion is called kinetic energy.
  • True
  • False
The form of energy stored in kerosene is:
  • chemical
  • heat energy
  • magnetic
  • mechanical
The form of energy that water stored in a dam primarily has is :
  • muscular energy
  • kinetic energy
  • potential energy
  • magnetic energy
Potential energy is directly proportional to:
  • velocity of the body
  • speed of the body
  • height of the body from the surface
  • shape of the body
A ball of mass m moving with velocity v collides elastically with another ball of identical mass coming from the opposite direction with velocity 2v. Their velocities after collision are :
  • $$-v,\:2v$$
  • $$-2v,\:v$$
  • $$v,\:-2v$$
  • $$2v,\:-v$$
The energy stored in a torch cell is :
  • Light energy
  • Electrical energy
  • Chemical energy
  • Potential energy
A body is acted upon by a force which is proportional to the distance covered. If distance covered by denoted by x, then work done by the force will be proportional to:
  • $$x$$
  • $$x^2$$
  • $$x^{\dfrac{3}{2}}$$
  • $$x^4$$
A body of mass 2$$\mathrm { Kg }$$ moving (initially) with 10$$\mathrm { m } / \mathrm { s }$$ is acting upon by a resultant constar which is opposite to its initial velocity. Its speed decreases to 4$$\mathrm { m } / \mathrm { s }$$ in 1 s. Then the force 
  • 12$$N$$
  • 28$$N$$
  • 8$$N$$
  • none
Velocity-time graph for a body of mass $$10\ kg$$ is shown in figure. Work-done on the body in first two seconds of the motion is : 

474803.JPG
  • $$- 9300\ J$$
  • $$12000\ J$$
  • $$- 4500\ J$$
  • $$- 12000\ J$$
When a rubber-band is stretched by a distance $$x$$, it exerts a restoring force of magnitude $$F = ax + bx^2$$ where $$a$$ and $$b$$ are constants. The work done in stretching the unstretched rubber band by $$L$$ is
  • $$\displaystyle \dfrac{aL^2}{2} + \dfrac{bL^3}{3}$$
  • $$\displaystyle \dfrac{1}{2} \left ( \dfrac{aL^2}{2} + \dfrac{bL^3}{3}\right )$$
  • $$aL^2 + bL^3$$
  • $$\displaystyle \dfrac{1}{2} (aL^2 + bL^3)$$
If collision between the block and the incline is completely elastic, then the vertical (upward) component of the velocity of the block at point B, immediately after it strikes the second incline is
43029.PNG
  • $$\sqrt{30}\mathrm{m}/\mathrm{s}$$
  • $$\sqrt{15}\mathrm{m}/\mathrm{s}$$
  • 0
  • $$-\sqrt{15}\mathrm{m}/\mathrm{s}$$
The balls, having linear momenta $$\vec{\mathrm{p}}_{1}=\mathrm{p}\hat{i}$$ and $$\vec{\mathrm{p}}_{2}=-\mathrm{p}\hat{\mathrm{i}}$$, undergo a collision in free space. There is no extemal force acting on the balls. Let $$\vec{\mathrm{p}}_{1}$$ and $$\vec{\mathrm{p}}_{2}$$ be their final momenta. The following option(s) is (are) NOT ALLOWED for any non-zero value of $$\mathrm{p},\ \mathrm{a}_{1},\ \mathrm{a}_{2},\ \mathrm{b}_{1},\ \mathrm{b}_{2},\ \mathrm{c}_{1}$$ and $$\mathrm{c}_{2}$$.
  • $$\vec{\mathrm{p}}_{1}=\mathrm{a}_{1}\hat{i}+\mathrm{b}_{1}\hat{\mathrm{j}}+\mathrm{c}_{1}\hat{\mathrm{k}}$$;

    $$\vec{\mathrm{p}}_{2}=\mathrm{a}_{2}\mathrm{i}+\mathrm{b}_{2}\hat{\mathrm{j}}$$
  • $$\vec{\mathrm{p}}_{1}=\mathrm{c}_{1}\hat{\mathrm{k}}$$;

    $$\vec{\mathrm{p}}_{2}=\mathrm{c}_{2}\hat{\mathrm{k}}$$
  • $$\vec{\mathrm{p}}_{1}=\mathrm{a}_{1}\mathrm{i}+\mathrm{b}_{1}\hat{\mathrm{j}}+\mathrm{c}_{1}\hat{\mathrm{k}}$$;

    $$\vec{\mathrm{p}}_{2}=\mathrm{a}_{2}\hat{\mathrm{i}}+\mathrm{b}_{2}\hat{\mathrm{j}}-\mathrm{c}_{1}\hat{\mathrm{k}}$$
  • $$\vec{\mathrm{p}}_{1}=\mathrm{a}_{1}\hat{\mathrm{i}}+\mathrm{b}_{1}\hat{\mathrm{j}}$$;

    $$\vec{\mathrm{p}}_{2}=\mathrm{a}_{2}\mathrm{i}+\mathrm{b}_{1}\hat{\mathrm{j}}$$
Two particles A and B, move with constant velocities $$\overrightarrow {v_1}$$ and $$\overrightarrow {v_2}$$. At the initial moment their position vectors are $$\overrightarrow {r_1}$$ and $$\overrightarrow {r_2}$$ respectively. The condition for particles A and B for their collision is:    
  • $$\overrightarrow {r_1} - \overrightarrow {r_2} = \overrightarrow {v_1} - \overrightarrow {v_2}$$
  • $$\displaystyle \frac{\overrightarrow {r_1} - \overrightarrow {r_2} }{\left |\overrightarrow {r_1} - \overrightarrow {r_2} \right|} = \displaystyle \frac{\overrightarrow {v_2} - \overrightarrow {v_1} }{\left |\overrightarrow {v_2} - \overrightarrow {v_1} \right|}$$
  • $$\overrightarrow {r_1} \cdot \overrightarrow {v_1} = \overrightarrow {r_2} \cdot \overrightarrow {v_2}$$
  • $$\overrightarrow {r_1} \times \overrightarrow {v_1} = \overrightarrow {r_2} \times \overrightarrow {v_2}$$
The force on a particle as the function of displacement x(in x-direction) is given by $$F=10+0.5x$$
The work done corresponding to displacement of particle from $$x=0$$ to $$x=2$$ unit is?
  • $$25$$ J
  • $$29$$ J
  • $$21$$ J
  • $$18$$ J
How much work must be done by a force on $$50\ $$$$kg$$ body in order to accelerate it from rest to $$20\ m/s$$  in $$10\ $$$$s$$ ?
  • $$10^3\ $$$$J$$
  • $$10^4\ $$$$J$$
  • $$2\times 10^3\ $$$$J$$
  • $$4\times 10^4\ $$$$J$$
The collision in which the relative velocity is zero after collision is
  • perfectly elastic
  • perfectly inelastic
  • partially elastic
  • sometimes elastic and sometimes inelastic
Complete the following sentence:
The potential energy of a body is the energy by virtue of its _______ .
  • motion
  • position
  • Both A and B
  • None of these
Which of the following will lead to a change in kinetic energy of a body?
  • change in its mass
  • change in its velocity
  • all of the above
  • none of the above
A lighter body moving with a velocity $$v$$ collides with a heavier body at rest. Then :
  • the lighter body rebounces with twice the velocity of bigger body
  • the lighter body retraces its path with the same velocity in magnitude
  • the heavier body does not move practically
  • both (2) and (3)

A spring is stretched up to its maximum length. The spring possesses which of the following forms of energy?
  • Kinetic energy
  • Elastic potential energy
  • Electric energy
  • Magnetic energy
The K.E. of a body can be increased maximum by doubling its:
  • mass
  • weight
  • speed
  • density
A body at maximum height possesses:
  • Kinetic energy
  • Potential energy
  • Solar energy
  • Heat energy
In SI system, the unit of P.E. is :
  • erg
  • dyne-cm
  • joule
  • none of these
Name the type of energy (kinetic energy $$K$$ or potential energy $$U$$) possessed in a compressed spring:
  • $$U$$
  • $$K$$
  • Both $$U$$ and $$K$$
  • None
Energy equals of a mass of one microgram in kilo joules is
  • $$9 \times 10^{7} kJ$$
  • $$10 \times 10^3 kJ$$
  • $$8 \times 10^2 kJ$$
  • $$7 \times 10^4 kJ$$
Complete the following sentence:
The kinetic energy of a body is the energy by virtue of its______ .
  • force
  • motion
  • roughness
  • all the above
The energy released on burning coal, oil, wood or gas is:
  • kinetic energy
  • heat energy
  • light energy
  • solar energy
Potential energy of the bob is maximum
  • at the mean position
  • at the extreme positions
  • between the mean position and extreme positions
  • none of these
Hydro-electric power generates
  • Electrical energy
  • Nuclear energy
  • Thermal energy
  • None of these
Heat is a form of :
  • Force
  • Energy
  • Work
  • Simple machine
A certain force acting on a body of mass 2kg increase its velocity from 6m/s to 15 m/s in 2s. The work done by the force during this interval is ?
  • 27J
  • 3J
  • 94.5J
  • 189J
A particle moves under the effect of a force $$F=Cx$$ form $$x=0$$ to $$x=x_{1}$$. The work done in the process is-
  • $$Cx_{1}^{2}$$
  • $$\displaystyle \frac{1}{2}Cx_{1}^{2}$$
  • $$Cx_{3}^{2}$$
  • zero
Which of the following has the highest Potential energy ?
  • 10 kg stone at a height of 20 m
  • 100 kg stone at a height of 2 rn
  • 40 kg stone at a height of 5 m
  • 30 kg stone at a height of 10 m
An electric heater converts electrical energy into
  • Chemical energy
  • Heat energy
  • Light energy
  • Muscular energy
One man takes one minute to raise a box to a height of 1 metre and another man takes 1/2 minute to do so. The energy of the two is .......
  • different
  • same
  • energy of the first is more
  • energy of the second is more
When an aeroplane takes off from the ground:
  • Kinetic energy increases and Potential energy decreases
  • Potential energy increases and Kinetic energy remains constant
  • both Kinetic energy and Potential energy remain constant
  • both Kinetic energy and Potential energy increase
A car is accelerating on a levelled plane and acquires a velocity $$3$$  times of its initial velocity. During this process, the potential energy of the car 
  • does not change
  • becomes $$1.5$$ times that of initial potential energy
  • becomes $$3$$ times that of initial potential energy
  • becomes $$9$$ times that of initial potential energy
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