List of top Physics Questions

A constant force of \[ \mathbf{F} = (8\hat{i} - 2\hat{j} + 6\hat{k}) \text{ N} \] acts on a body of mass 2 kg, displacing it from \[ \mathbf{r_1} = (2\hat{i} + 3\hat{j} - 4\hat{k}) \text{ m to } \mathbf{r_2} = (4\hat{i} - 3\hat{j} + 6\hat{k}) \text{ m}. \] The work done in the process is:

If \( dQ, dU, dW \) are heat energy absorbed, change in internal energy, and external work done respectively by a diatomic gas at constant pressure, then \( dW : dU : dQ \) is:
Regarding fundamental forces in nature, the correct statement is
A bob is whirled in a horizontal circle by means of a string at an initial speed of 10 rpm. If the tension in the string is quadrupled while keeping the radius constant, the new speed is:

A particle is moving along x-axis with its position ($ x $) varying with time ($ t $) as:  
$ x = \alpha t^4 + \beta t^2 + \gamma t + \delta. $  
The ratio of its initial velocity to its initial acceleration, respectively, is:

Match List I with List II.
List I
(Spectral Lines of Hydrogen for transitions from)		List II
(Wavelength (nm))
A.n2 = 3 to n1 = 2I.410.2
B.n2 = 4 to n1 = 2II.434.1
C.n2 = 5 to n1 = 2III.656.3
D.n2 = 6 to n1 = 2IV.486.1
Choose the correct answer from the options given below:
At room temperature, gaseous hydrogen is bombarded with a beam of electrons of 13.6 eV energy. The series to which the emitted spectral line belongs to:
If a ray of light passes through an equilateral prism such that the angle of incidence and the angle of emergence are both equal to 70\% of the angle of the prism, then the angle of minimum deviation is:
The density of a substance of mass 5.318 g which occupies a volume of 2.43 cm³ is (up to correct significant figures):
Two spherical rain drops of radii in the ratio 4:5 are falling vertically through air. The ratio of the terminal velocities of the rain drops is:
The efficiency of a reversible heat engine working between two temperatures is 50\%. The coefficient of performance of a refrigerator working between the same two temperatures but in reverse direction is:
The concentration of electrons in an intrinsic semiconductor is \( 6 \times 10^{15} \, m^{-3} \). On doping with an impurity, the electron concentration increases to \( 4 \times 10^{22} \, m^{-3} \). In thermal equilibrium, the concentration of the holes in the doped semiconductor is:
The half-life of a radioactive substance is 12 minutes. The time gap between 28\% decay and 82\% decay of the radioactive substance is:
An element consists of a mixture of three isotopes A, B, and C of masses \( m_1 \), \( m_2 \), and \( m_3 \) respectively. If the relative abundances of the three isotopes A, B, and C is in the ratio 2:3:5, the average mass of the element is:
A cannon fires two similar shells one after the other each with a velocity of 100 m/s at angles 60$^\circ$ and 30$^\circ$ respectively with the horizontal such that they both hit the target at the same time. The time interval between the firing of the two shells is (Acceleration due to gravity = 10 m/s²).
An arc making an angle \(15^\circ\) at the center is removed from a ring of mass \( M \) and radius \( R \). The moment of inertia of the remaining ring about an axis passing through its center and perpendicular to its plane is:
A liquid drop of diameter 2 mm breaks into 125 identical drops, then the change in the surface energy is:
The speed of a transverse wave in a stretched string 'A' is 'v'. Another string 'B' of same length and same radius is subjected to same tension. If the density of the material of the string 'B' is 2\% more than that of 'A', then the speed of the transverse wave in string 'B' is
Two identical balls having like charges placed at a certain distance apart, repel each other with a force \( F \). When they are brought in contact and then moved apart to a distance equal to half of their initial separation, the force of repulsion between them becomes \( 4.5F \). The ratio of the initial charges of the balls is:
A liquid drop of diameter 2 mm breaks into 125 identical drops, then the change in the surface energy is:
A cannon fires two similar shells one after the other each with a velocity of 100 m/s at angles 60$^\circ$ and 30$^\circ$ respectively with the horizontal such that they both hit the target at the same time. The time interval between the firing of the two shells is (Acceleration due to gravity = 10 m/s²).
Two solid spheres of radii \( r_1 \) and \( r_2 \) (\( r_2>r_1 \)) made of the same material are kept in contact. The distance of their center of mass from their point of contact is:
If the tension applied to a string is decreased by 36\%, then the fundamental frequency of the transverse waves of the string is:
A supposition without assuming that it is true is:
A block is kept on a rough horizontal surface. The acceleration of the block increases from \( 6 \ ms^{-2} \) to \( 11 \ ms^{-2} \) when the horizontal force acting on it increases from \( 20 \ N \) to \( 30 \ N \). The coefficient of kinetic friction between the block and the surface is: (Acceleration due to gravitiy = 10ms-^2)