Physics

Q.

An object 5.0 cm in length is placed at a distance of 20 cm in front of a convex mirror with a radius of curvature of 30 cm. Find the position of the image, its nature, and size.

Q.

How do I convert $m/s$ to $km/h$? Give an example

Q.

A person sitting on the ground floor of a building notices through the window, of height 1.5 m, a ball dropped from the roof of the building and crosses the window in 0.1 s. What is the velocity of the ball when it is at the topmost point of the window? (g-10 m/$s^2$)

(1) 20 m/s

(2) 15.5 m/s

(3) 14.5 m/s

(4) 4.5 m/s

Q.

Starting from $\left(-1\right)\times 5$, write various products showing some pattern to show $\left(-1\right)\times \left(-1\right)=1$.

Q.

What is the ratio of the distance traveled by a body falling freely from rest in the first, second, and third seconds of its fall?

Q.

If the K.E. of a body is increased by 300%, its momentum will increase by

1. 100%

2. 150%

3. 

4. 175%

Q.

What is the derivative of $\sin \left(2x\right)$?

Q. If x = e5t where x is the position of a particle in meter, then position of the particle at time t = 1 s is equal to

Q.

What is the difference between stable, unstable and neutral equilibrium? what is equilibrium?

Q.

The force required to stretch a steel wire of $1c{m}^2$ cross - section to 1.1 times its length would be $(Y=2\times {10}^{11}N{m}^{-2})$

1. 
2. 
3. 
4. 

Q.

A driver of a car traveling at 52 km h^-1 applies the brakes and accelerates uniformly in the opposite direction. The car stops in 5 s. Another driver going at 3 km h^-1 in another car applies his brakes slowly and stops in 10 s. On the same graph paper, plot the speed versus time graphs for the two cars. Which of the two cars traveled farther after the brakes were applied?

Q. Two particles are oscillating along two close parallel straight lines side by side, with the same frequency and amplitudes. They pass each other, moving in opposite directions when their displacement is half tof the amplitude. The mean positions of the two O particles lie on a straight line perpendicular to the paths of the two particles. The phase difference is s

Q. 62 The suns angular diameter is measured to be 1920". The distance D of the sun from the earth is 1.49610 to the power 11 find the diameter of the sun.

Q.

What is $v=u+at$?

Q.

A man walks on a straight road from his home to a market 2.5 km away with a speed of 5 km/h. Finding the market closed, he instantly turns and walks back home with a speed of 7.5 km/h. If the total time of travel is 40 min find the average speed of the man for the whole journey.

1. 5 km/h

2. 

3. 

4. 

Q.

What are supplementary quantities?

Q.

A mass falls from a height ‘h’ and its time of fall ‘t’ is recorded in terms of time period T of a simple pendulum. On the surface of earth it is found that t = 2T. The entire set up is taken on the surface of another planet whose mass is half of that of earth and radius the same. Same experiment is repeated and corresponding times noted as t' and T'. Then we can say

Q.

Viscosity of gases _______with temperature, whereas viscosity of liquids _______with temperature.

Q.

The minimum energy required to launch a satellite of mass m from the surface of earth of radius R in a cirulcar orbit at an altitude 2R is (mass of earth is M)

1. 

2. 

3. 

4. 

Q.

Pressure inside two soap bubbles are 1.01 and 1.02 atmospheres. Ratio between their volumes is

1. 2 : 1

2. 102 : 101

3. (102)³ : (101)³

4. 8 : 1

Q. Electric field inside an uniformly charges non conducting sphere

Q.

The height above the Earth's surface at which the value of acceleration due to gravity reduces to half its value on the Earth's surface is h. Assume the Earth to be a sphere of radius 6400 Km. Find h.

1. 3650 km

2. 2650 km

3. 4650 km

4. 1650 km

Q. A parachutist after bailing out falls 50 m without friction. When parachute opens, it decelerates at $2\frac{m}{s^2}$. He reaches the ground with a speed of $3\frac{m}{s}$. At what height, did he bail out ?

1. 111 m
2. 91 m
3. 293 m
4. 182 m

Q. An electron is accelerated through a potential difference of $10,000V$. Its de Broglie wavelength is (nearly) $\left(m_e=9\times {10}^{-31}kg\right)$

1. $12.2\times {10}^{-13}m$
2. $12.2\times {10}^{-12}m$
3. $12.2\times {10}^{-14}m$
4. $12.2nm$

Q. cooling rate of a sphere of 600 K at external environment (200 K) is R. When the temperature of sphere is reduced to 400 K then cooling rate of the sphere becomes : (1) 3/16 R (2) 16/3 R (3) 9/27 R (4) None

Q.

The root mean square (R.M.S.) Speed V of the molecules of an ideal gas is given by the expressions,

v = √ (3RT/M) and

v = √ (3KT/m) where R is universal gas constant, T is the absolute (Kelvin) temperature M is the molar mass, K is Boltzman's constant and M is the molecular mass. The R.M.S. speed of oxygen molecules (O₂) at temperature T₁ is V₁. When the temperature is doubled, if the oxygen molecules are dissociated into atomic oxygen, what will be R.M.S. speed of oxygen atoms? (Treat the gas as ideal).

1. v₁/2

2. v₁

3. 2v₁

4. 

Q. if the percent error in the measurement of momentum and mass of an object are 2 percent and 3 percent then maximum percentage error in the calculated value of its kinetic energy i

Q. An electric dipole of dipole moment p is lying along uniform electric field E.work done in rotating the dipole by 90 degree is

Q. A light-year is a unit of

1. time
2. mass
3. distance
4. energy

Q. 23. The enthalpy change (H) for the reaction, N2(g) + 3H2(g) 2NH3(g) is –92.38 kJ at 298 K. What is U at 298 K?