List of top Physics Questions

The length of a simple pendulum which makes 20 oscillations in 36 seconds (at place where the acceleration due to gravity $9.75 m/s^2$ ) is
In an experiment, on the measurement of g using a simple pendulum, the time period was measured with an accuracy of 0.2% while the length was meausred with an accuracy of 0.5%. The percentage accuracy in the value of g thus obtained is
An carthquake gencrates both transverse $(S)$ and longitudinal $(P)$ sound waves in the earth. The spced of $S$ waves is about $4.5 \,km / s$ and that of $P$ waves is about $8.0 \,km / s$. A scismograph records $P$ and $S$ wavcs from an carthquake. The first $P$ wave arrives $4.0\, min$ before the first $S$ wave. The cpicentre of the earthquake is located at a distance about
A rocket with a lift-off mass $3.5 \times 10^4$ kg is blasted upwards with an initial acceleration of ${10 \, m \, s^{-2}}$. Then the initial thrust blast is
A moving coil galvanometer of resistance 100 $\Omega$ is used as an ammeter using a resistance 0.1 $\Omega$. The maximum deflection current in the galvanometer is 100 $\mu$A. Find the minimum current in the circuit, so that the ammeter shows maximum deflection
A boy standing between two cliffs claps and hear two echoes, the first after 2 seconds and the second after 3 seconds. The velocity of sound is 360 m/sec. The distance in meter between the two cliffs is
On a particular day, the maximum frequency reflected from the ionosphere is 9 MHz. On another day, it was found to increase by 1 MHz. What is the ratio of the maximum electron densities of the ionosphere on the two days?
The length of an elastic string is a metre, when the longitudinal tension is 4 N and the length is $b$ m, when the tension is 5 N. When the longitudinal tension is 9 N, the length of the string (in metre) is
A man standing on the road has to hold his umbrella at 30 degrees from the vertical direction to keep the rain away. He thrown away the umbrella and starts running at ${10\, km \, h^{-1}}$, he finds that the rain drops are hitting him vertically. The speed of the rain drops w.r.t. the road is
A bus travelling the first one-third distance at a speed of ${10 \, km \, h^{-1}}$, the next one-third at ${20 \, km \, h^{-1}}$ and last one third at ${60 \, km \, h^{-1}}$. The average speed of bus is
A projectile is fired vertically upwards from the surface of the Earth with a velocity $k\upsilon _e$ , where $\upsilon_e$ is the escape velocity and $k < 1$ . If $R$ is the radius of the Earth, the maximum height to which it will rise measured from the centre of the Earth will be
The component of a vector $\vec{r}$ along $x$-axis will have maximum value if
A conducting wire carrying current is arranged as shown. The magnetic field at $'O'$
The position vector $\vec{r}$ of a particle of mass $m$ is given by the following equation $\vec{r}(t)=\alpha t^{3} \hat{i}+\beta t^{2} \hat{j}$ where $\alpha=\frac{10}{3} \,ms ^{-3}, \beta=5\, ms ^{-2}$ and $m =0.1 \,kg$. At $t =1\, s$, which of the following statement (s) is (are) true about the particle?
Magnitude of binding energy of satellite is $E$ and kinetic energy is $K$ .The ratio $E/K$ is
The frequencies of $X-$ rays, Gamma rays and visible light waves rays are $a, b$ and $c$ respectively, then
An electron is at ground state of the $H$ atom. Minimum energy required to excite the $H$ atom into second excited state is
In the given circuit, charge $Q_2 $ on the $2 \mu F $ capacitor changes as $C$ is varied from $1 \mu F $ to $3 \mu F. $ $Q_2 $ as a function of $'C'$ is given properly by (figures are drawn schematically and are not to scale)
A uniformly charged solid sphere of radius $R$ has potential $V _{0}\, 9$ measured with respect to $\infty$ ) on its surface. For this sphere the equipotential surfaces with potentials $\frac{3 V _{0}}{2}$, $\frac{5 V _{0}}{4}, \frac{3 V _{0}}{4}$ and $\frac{ V _{0}}{4}$ have radius $R _{1}, R _{2}, R _{3}$ and $R _{4}$ respectively. Then
In the following figure is shown a system of four capacitors connected across a $10\, V$ battery. Charge that will flow from switch $S$ when it is closed is
A proton (mass m) accelerated by a potential difference $V$ flies through a uniform transverse magnetic field $B$. The field occupies a region of space by width $d$. If $\alpha$ be the angle of deviation of proton from initial direction of motion (see figure), the value of $\sin \,\alpha$ will be :
Two coaxial solenoids of different radii carry current $I$ in the same direction. Let $\vec{F}_1$ be the magnetic force on the inner solenoid due to the outer one and $\vec{F}_2$ be the magnetic force on the outer solenoid due to the inner one. Then,
When current in a coil changes from $5 \,A$ to $2 \,A$ in $0.1\, s$, an average voltage of $50\, V$ is produced. The self - inductance of the coil is :
A train is moving on a straight track with speed $20\, ms^{-1}.$ It is blowing its whistle at the frequency of $1000\, Hz$. The percentage change in the frequency heard by a person standing near the track as the train passes him is close to (speed of sound $= 320\,ms^{-1}$)
The rate of volume occupied by an atom to the volume of the nucleus is