A spherical black body with a radius of 12 cm radiates 450 watt power at 500 K. If the radius were halved and the temperature doubled, the power radiated in watt would be
- A225
- B450
- C1800
- D1000
Question types
Model Paper 3 question types
38 questions across 6 question groups — pick any mix to generate a Physics paper with step-by-step answer keys.
38
Questions
6
Question groups
5
Question types
01
M.C.Q (1 Marks)
12 Q→022 Marks Questions
6 Q→033 Marks Question
8 Q→045 Marks Questions
6 Q→05Case study (4 Marks)
2 Q→06Assertion (A) & Reason (B) MCQ
4 Q→Sample Questions
Model Paper 3 questions
One sample from each question group in this chapter. Select any group above to see the full set with answer keys.
A thin uniform rod of length $2 l$ and mass M is acted upon a constant torque. The angular velocity changes from zero to $\omega$ in time $t$. The value of torque is:
- A$\frac{M l^2 \omega}{3 t}$
- B$\frac{2 M l^2 \omega}{3 t}$
- C$\frac{M l^2 \omega}{12 t}$
- D$\frac{M l^2 \omega}{t}$
Satellites orbiting the earth have a finite life and sometimes debris of satellites fall to the earth. This is because,
- Aof viscous forces causing the speed of the satellite and hence height to gradually decrease.
- Bthe solar cells and batteries in satellites run out.
- Cof collisions with other satellites.
- Dthe laws of gravitation predict a trajectory spiralling inwards.
An open tank filled with water (depsity $\rho$ ) has a narrow hole at a depth of h below the water surface. The velocity of water flowing out is
- A2 gh
- B$\sqrt{2 g h}$
- C$h \rho g$
- Dgh
The phase difference between two waves, represented by
$
\begin{aligned}
& y_1=10^{-6} \sin \left[100 t+\left(\frac{x}{50}\right)+0.5\right] m \\
& y_2=10^{-6} \cos \left[100 t+\left(\frac{x}{50}\right)\right] m
\end{aligned}
$
where x is expressed in metres and $t$ is expressed in seconds, is approximately
$
\begin{aligned}
& y_1=10^{-6} \sin \left[100 t+\left(\frac{x}{50}\right)+0.5\right] m \\
& y_2=10^{-6} \cos \left[100 t+\left(\frac{x}{50}\right)\right] m
\end{aligned}
$
where x is expressed in metres and $t$ is expressed in seconds, is approximately
- A1.07 rad
- B1.5 rad
- C0.5 rad
- D2.07 rad
An astronaut, by mistake, drops his food packet from an artificial satellite orbiting around the earth. Will it reach the surface of the earth? Why?
At a point above the surface of the earth, the gravitational potential is $-5.12 \times 10^7 J / kg$ and the acceleration due to gravity is $6.4 m / s ^2$. Assuming the mean radius of the earth to be 6400 km , calculate the height of the point above the earth's surface.
View full solution →Is friction a non-conservative force?
The density of mercury is $13.6 g cm ^{-3}$ in CGS system. Find its value in SI units.
View full solution →Differentiate between dimensional and non-dimensional variables.
What is venturi-meter? On which principle does it work? How is the principle of venturi-meter applied in automobiles?
Mercury has an angle of contact equal to $140^{\circ}$ with soda-lime glass. A narrow tube of radius 1.00 mm made of this glass is dipped in a trough containing mercury. By what amount does the mercury dip down in the tube relative to the liquid surface outside? Surface tension of mercury at the temperature of the experiment is 0.465 N $m ^{-1}$. Density of mercury $=13.6 \times 10^3 kgm ^{-3}$. .
View full solution →How is centripetal force provided in case of the following?
i. Motion of planet around the sun,
ii. Motion of moon around the earth.
iii. Motion of an electron around the nucleus in an atom.
i. Motion of planet around the sun,
ii. Motion of moon around the earth.
iii. Motion of an electron around the nucleus in an atom.
If, at $50^{\circ} C$ and 75 cm of mercury pressure, a definite mass of a gas is compressed
i. slowly
ii. suddenly, then what will be the final pressure and temperature of the gas in each case if the final volume is one-fourth of the initial volume? $(\gamma=1.5)$
View full solution →i. slowly
ii. suddenly, then what will be the final pressure and temperature of the gas in each case if the final volume is one-fourth of the initial volume? $(\gamma=1.5)$
Show that Newton's third law of motion is contained in the second law.
A metre scale AB is held vertically with its one end A on the floor and is then allowed to fall. Find the speed of the other end B when it strikes the floor, assuming that the end on the floor does not slip.
Derive an expression for moment of inertia of a circular disc about an axis passing through its centre and perpendicular to its plane.
$\hat{i}$ and $\hat{j}$ are unit vectors along x and y -axes respectively. What is the magnitude and direction of vectors $\hat{i}+\hat{j}$ and $\hat{i}$ $\hat{j}$ ? What are the components of a vector $A =2 \hat{ i }+3 \hat{ j }$ along the direction $\hat{i}+\hat{j}$ and $\hat{i}-\hat{j}$ ?
View full solution →What is meant by resolution of a vector? Prove that a vector can be resolved along two given directions in one and only one way.
Two identical springs, each of spring factor k, may be connected in the following ways. Deduce the spring factor of the oscillation of the body in each case.
Gas molecules move in random motion inside the container. The pressure exerted by the gas is due to the continuous collision of the molecules against the walls of the container. Due to this continuous collision, the walls experience a continuous force which is equal to the total momentum imparted to the walls per second.
1. If the mass of each molecule is halved and speed is doubled, find the ratio of initial and final pressure:
(a) $1: 16$ (b) $1: 4$ (c) $1: 8$ (d) $1: 2$
2. The pressure exerted by the gases is:
(a) inversely proportional to the density
(b) inversely proportional to the square of the density
(c) directly proportional to the density
(d) directly proportional to the square of the density
3. If the force of attraction between the molecules suddenly disappears, then what will be the change in pressure:
(a) pressure increase
(b) pressure decrease
(c) pressure remains constant
(d) pressure falls
4. If the pressure of a given gas is halved at a certain temperature. what will be its volume:
(a) becomes triple (b) becomes double (c) remains constant (d) becomes half
OR
Dimension formula for R ?
(a) $M ^1 L^2 T^2 K^{-1}$ (b) $M ^1 L^1 T^{-1}$
(c) $M ^{-1} L^0 T^1$ (d) $M ^1 L^2 T^{-2} K^{-1}$
View full solution →1. If the mass of each molecule is halved and speed is doubled, find the ratio of initial and final pressure:
(a) $1: 16$ (b) $1: 4$ (c) $1: 8$ (d) $1: 2$
2. The pressure exerted by the gases is:
(a) inversely proportional to the density
(b) inversely proportional to the square of the density
(c) directly proportional to the density
(d) directly proportional to the square of the density
3. If the force of attraction between the molecules suddenly disappears, then what will be the change in pressure:
(a) pressure increase
(b) pressure decrease
(c) pressure remains constant
(d) pressure falls
4. If the pressure of a given gas is halved at a certain temperature. what will be its volume:
(a) becomes triple (b) becomes double (c) remains constant (d) becomes half
OR
Dimension formula for R ?
(a) $M ^1 L^2 T^2 K^{-1}$ (b) $M ^1 L^1 T^{-1}$
(c) $M ^{-1} L^0 T^1$ (d) $M ^1 L^2 T^{-2} K^{-1}$
The kinetic energy of an object is the energy associated with the object which is under motion. It is defined as "the energy required by a body to accelerate from rest to stated velocity." It is a vector quantity and the momentum of an object is the virtue of its mass. It is defined as the product of mass and velocity. It is a vector quantity. The relation between them is given by $E =\frac{P^2}{2 m}$. In case of the elastic collision both of these quantities remain constant.
1.Two masses of 1 gm and 4 gm are moving with equal linear momentum. The ratio of their kinetic energy is:
(a) $1: 2$ (b) $4: 1$ (c) $1: 1$ (d) $4: 2$
2. If the linear momentum is increased by $50 \%$, then K .E will be increased by:
(a) $50 \%$ (b) $200 \%$ (c) $125 \%$ (d) $100 \%$
3.A heavy object and a light object have the same momentum. Which has the greater speed?
(a) both heavy and light object
(b) heavy object
(c) Moderate object
(d) light object
OR
Kinetic energy with any reference must be $\qquad$
(a) Change (b) negative (c) zero (d) positive
4.When a body moves with a constant speed along a circle then
(a) no acceleration is produced
(b) no work is done on it
(c) no displacement on it
(d) no force acts on it
View full solution →1.Two masses of 1 gm and 4 gm are moving with equal linear momentum. The ratio of their kinetic energy is:
(a) $1: 2$ (b) $4: 1$ (c) $1: 1$ (d) $4: 2$
2. If the linear momentum is increased by $50 \%$, then K .E will be increased by:
(a) $50 \%$ (b) $200 \%$ (c) $125 \%$ (d) $100 \%$
3.A heavy object and a light object have the same momentum. Which has the greater speed?
(a) both heavy and light object
(b) heavy object
(c) Moderate object
(d) light object
OR
Kinetic energy with any reference must be $\qquad$
(a) Change (b) negative (c) zero (d) positive
4.When a body moves with a constant speed along a circle then
(a) no acceleration is produced
(b) no work is done on it
(c) no displacement on it
(d) no force acts on it
Assertion (A): The division of a vector by another vector is not defined.
Reason (R): The division of a vector by a direction is not possible.
Reason (R): The division of a vector by a direction is not possible.
- ABoth A and R are true and R is the correct explanation of A.
- BBoth A and R are true but R is not the correct explanation of A.
- CA is true but R is false.
- DA is false but R is true.
Assertion (A): Even when orbit of a satellite is elliptical, its plane of rotation passes through the centre of earth.
Reason (R): According to law of conservation of angular momentum plane of rotation of satellite always remain same.
Reason (R): According to law of conservation of angular momentum plane of rotation of satellite always remain same.
- ABoth A and R are true and R is the correct explanation of A.
- BBoth A and R are true but R is not the correct explanation of A.
- C
- DA is false but R is true.
Assertion: In an isochoric process, work done by the gas is zero.
Reason: In a process, if initial volume is equal to the final volume, work done by the gas is zero.
Reason: In a process, if initial volume is equal to the final volume, work done by the gas is zero.
- AAssertion and reason both are correct statements and reason is correct explanation for assertion.
- BAssertion and reason both are correct statements but reason is not correct explanation for assertion.
- CAssertion is correct statement but reason is wrong statement.
- DAssertion is wrong statement but reason is correct statement.
Assertion (A): The Work-Energy theorem is applicable for non-inertial frames also.
Reason (R): The Work-Energy theorem is applicable to non-inertial frames provided we include the pseudo forces in the calculation of the net force acting on the body under consideration.
Reason (R): The Work-Energy theorem is applicable to non-inertial frames provided we include the pseudo forces in the calculation of the net force acting on the body under consideration.
- ABoth A and R are true and R is the correct explanation of A.
- BBoth A and R are true but R is not the correct explanation of A.
- CA is true but R is false.
- DA is false but R is true.
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