List of top Physics Questions

An electron moving with a speed u along the positive x-axis at y = 0 enters a region of uniform magnetic field $B=-B_0 k$ which exists to the right of v-axis. The electron exits from the region after sometime with the speed v at coordinate y, then
Carbon dating is best suited for determining the age of fossils if their age in years is of the order of
The dimension of light year is :
When a resistance of $\alpha\, \Omega$ is connected at the ends of a battery, its potential difference decreases from $40\, V$ to $30\, V$. The internal resistance of the battery is
For the post office box arrangement to determine the value of unknown resistance, the unknown resistance should be connected between
A galvanometer gives full scale deflection with $0.2\, A$ in a coil shown in the figure. The resistance of its coil is $ 10\,\Omega $ . How much shunt resistance is required to convert it into an ammeter to read current upto $1.8\, A$ ?
The thermo emf of a thermocouple varies with the temperature $?$ of the hot junction as $E = a \,? + b?^2$ in volts where the ratio $a/b$ is $700^{\circ}C$. If the cold junction is kept at $0^{\circ}C$, then the neutral temperature is
An electric current is passed through a circuit containing two wires of the same material, connected in parallel. If the length and radii of the wires are in the ratio of $4/3$ and $2/3$, then the ratio of the currents passing through the wire will be
A larger dry cell has higher emf. The emf of a dry cell is proportional to its size.
Current provided by a battery is maximum when:
In a metre bridge experiment null point is obtained at $20\, cm$ from one end of the wire when resistance $X$ is balanced against another resistance $Y$. If $X < Y$, then where will be the new position of the null point from the same end, if one decides to balance a resistance of $4X$ against $Y$ ?
The resistance of tungsten filament at $150^{\circ} C$ is $133 \Omega$ what will be its resistance at $500^{\circ} C$ ? The temperature coefficient of resistance of tungsten is $0.0045 /{ }^{\circ} C$.
The resistance of the series combination of two resistances is $S$. When they are joined in parallel through total resistance is $P$. If $S = nP$, then the minimum possible value of $n$ is
The thermistors are usually made of
A block P of mass m is placed on a horizontal frictionless plane. A second block of same mass m is placed on it and is connected to a spring of spring constant k, the two blocks are pulled by a distance A. Block Q oscillates without slipping. What is the maximum value of frictional force between the two blocks?
A spring has length $I$ and spring constant $k$. If spring is divided in two equal pans then spring constant of each part is:
The total energy of particle, executing simple harmonic motion is
Two springs are connected to a block of mass $M$ placed on a frictionless surface as shown below. If both the springs have a spring constant $k$, the frequency of oscillation of the block is
A simple pendulum has time period $T$. The bob is given negative charge and surface below it is given positive charge. The new time period will be:
The bob of a simple pendulum executes simple harmonic motion in water with a period $t$, while the period of oscillation of the bob is $t_0$ in air. Neglecting frictional force of water and given that the density of the bob is $\left(\frac{4}{3}\right)\times1000\,kg/m^{3}.$ What relationship between $t$ and $t_0$ is true?
A particle of mass $m$ is attached to a spring (of spring constant $k$) and has a natural angular frequency $\omega_0$. An external force $F(t)$ proportional to $cos\omega t$ $(\omega?\omega_0)$ is applied to the oscillator. The time displacement of the oscillator will be proportional to
If for a particle executing SHM, the equation of SHM is given as y= a cos $\omega$t Then which of the following graph represents the variation in its potential energy?
A simple pendulum is vibrating in an evacuated chamber, it will oscillate with:
A spring executes SHM with mass of $10 \,kg$ attached to it. The force constant of spring is $10\, N / m$. If at any instant its velocity is $40 \,cm / sec$, the displacement will be (where amplitude is $0.5 \,m$ ) :
How is the time period of simple pendulum vary with its amplitude?