Recent questions in Physics

A river of salty water is flowing with a velocity 2 m/sec. If the density of the water is $1.2\;gm/c.c$, then the kinetic energy of each cubic metre of water is

asked Oct 18, 2013 by meena.p

1 answer

If a body is projected with an angle $\theta$ to the horizontal, then

asked Oct 18, 2013 by meena.p

1 answer

A body thrown vertically up to reach its maximum height in t seconds. The total time from the time of projection to reach a point at half of its maximum height while returning (in seconds) is

asked Oct 18, 2013 by meena.p

1 answer

The component of vector $\bar {A}= a_x \hat i + a _y \hat j + a _z \hat k$ along the direction of $\hat i- \hat j$ is

asked Oct 18, 2013 by meena.p

1 answer

The energy (E), angular momentum (L) and universal gravitational constant(G) are chosen as fundamental quantities. The dimensions of universal gravitational constant in the dimensional formula of Planks constant (h) is

asked Oct 18, 2013 by meena.p

1 answer

A wheel of radius 0.4 m can rotate freely about its axis as shown in the figure. A string is wrapped over its rim and a mass of 4 kg is hung. An angular acceleration of $8\;rad-s^{-2}$ is produced in it due to the torque. Then moment of inertia of the wheel is :

asked Oct 14, 2013 by meena.p

1 answer

A rod of length l is held vertically stationary with its lower and located at a point 'P', on the horizontal plane. When the rod is released to topple about 'P', the velocity of the upper end of the rod with which it hits the ground is :

asked Oct 14, 2013 by meena.p

1 answer

Two persons A and B are located in X-Y plane at the points at the points (0,0) and (0,10) respectively. (The distance are measured in MKS units). At a time $t=0$, they start moving simultaneously with velocities $\bar {v}_A=2 \hat j m/s$ and $\bar v_B=2 \hat i m/s$ respectively. The time after which A and B are at their closest distance is :

asked Oct 14, 2013 by meena.p

1 answer

A bullet of mass $0.02\;kg$ travelling horizontally with velocity $250\;ms^{-1}$ strikes a block of wood of mass $0.23\;kg $ which rests on a rough horizontal surface. After the impact, the block and bullet move together and come to rest after travelling a distance of $40\;m$ . The coefficient of sliding friction of the rough surface is : $(g=9/8 ms^{-2})$

asked Oct 14, 2013 by meena.p

1 answer

Currents flowing in each of the following circuits A and B respectively are :

asked Oct 14, 2013 by meena.p

1 answer

The radio activity of a sample is $'X'$ at a time $'t_1'$ and $'Y'$ at a time '$t_2'$. If the mean life time of the specimen is 't', the number of atoms that have disintegrated in the time interval $(t_1-t_2)$ is :

asked Oct 14, 2013 by meena.p

1 answer

A photon of energy 'E' ejects a photo electron from a metal surface whose work function is $W_0$. If this electron enters into a uniform magnetic field of induction 'B' in a direction perpendicular to the field and describes a circular path of radius 'R' , then the radius 'r' is given by , (in the usual notation):

asked Oct 14, 2013 by meena.p

2 answers

The work function of a certain metal is $3.31 \times 10^{-19}\;J$. Then the maximum kinetic energy of photo electrons emitted by radiation of wavelength 5000 A is : (given $h=6.62 \times 10^{-34}\;J-s, C= 3 \times 10^{8}ms^{-1},e= 1.6 \times 10^{-19}$ coul.)

asked Oct 14, 2013 by meena.p

1 answer

An infinitely long straight conductor is bent into the shape as shown below. It carries a current of i Amps, and the circular loop is R meters. Then the magnitude of magnetic induction at the center of the circular loop is :

asked Oct 14, 2013 by meena.p

1 answer

A wire of length 'l' is bent into a circular loop of radius R and carries a current I. The magnetic field at the center of the loop is 'B'. The same wire is now bent into a double loop of equal radii. If both loops carry the same current I and it is in the same direction, the magnetic field at the center of the double loop will be :

asked Oct 14, 2013 by meena.p

1 answer

The following series $L-C-R$ circuit, when driven by an e.m.f source of angular frequency 70 Kilo-radius per second, the circuit effectively behaves like :

asked Oct 14, 2013 by meena.p

1 answer

A cell in secondary circuit gives null deflection for $2.5\;m$ length of potentiometer having 10 m length of wire. If the length of the potentiometer wire is increased by 1 m without changing the cell in the primary, the position of the null point now is :

asked Oct 14, 2013 by meena.p

1 answer

In the circuit shown below, a voltmeter of internal resistance R, When connected across B and C reads $\large\frac{100}{3}$ volts. Neglecting the internal resistance of the battery, the value of R is :

asked Oct 14, 2013 by meena.p

1 answer

Two point charges $-q$ and $+q$ are located at points $(0,0,-a)$ and $(0,0,a)$ respectively.The electric potential at a point $(0,0,z)$ where $ z > a$ is :

asked Oct 14, 2013 by meena.p

1 answer

An infinitely long thin straight wire has uniform linear charge density of $ \large\frac{1}{3}\;$$ coul.m^{-1}. $ Then the magnitude of the electric intensity at a point 18 cm away is : (given $\in _{0}=8.8 \times 10^{-12} C^2 /N-m^2)$

asked Oct 14, 2013 by meena.p

1 answer

The emf of a cell E is 15 V as shown in the figure with an internal resistance of $ 0.5 \Omega $. Then the value of the current drawn from the cell is

asked Oct 13, 2013 by thanvigandhi_1

1 answer