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Practice Online Test Series for JEE Main 2018 & NEET 2018
In a n-type semiconductor, which of the following statement is true:
If a charge particle at rest experiences no electromagnetic force:
Three charges `-sqrt2 muC, 2sqrt2 muC` and `-sqrt2 muC` are arranged along a straight line as shown in the figure. Calculate the total electric field intensity due to all three charges at the point P:
An anisotropic material has coefficients of linear thermal expansion `alpha_1, alpha_2` and `alpha_3` along x, y and z-axis respectively. Coefficient of cubical expansion of this material will be equal to:
A block slides down an inclined plane with an acceleration `g/2` as shown in fig. Then coefficient of kinetic friction is:
Consider the following reaction
The atomic masses are given as
The Q- value of the above reaction will be
Magnetic field at the centre C of circular arc is:
Charges `Q_1` and `Q_2` lies inside and outside respectively of a closed surface S. Let E be the field at any point on S and phi be the flux of E over S. Which statement is wrong?
Pressure at the bottom of a tank of water is 3P, where P is atmospheric pressure. If the water is drawn out till the level of water is lowered by one fifth, then the pressure at the bottom of the tank is:
A ball is dropped from a height. If it takes 1 sec to cross the last 55m before hitting the ground find the height from which it was dropped:
The decay rate of sample of radioactive nuclide `I^128` after time 4 min and 36 min is 322 and 161 counts/s. Find half lite for this radionuclide.
Find magnetic field at point P in given dis:
If electric potential energy of given system is positive then:
The surface tension of soap solution is 0.03 N/m. The work done in blowing to form a soap bubble of surface area 40 c`m^2` is:
The displacement time graph of a particle moving on the X-axis is given below:
Then:
Atomic weight of thorium is A =323 and the atomic number is Z=90. After disintergation to last element Pb is obtained which has A=208 and Z=82. In this process the number of emitted `alpha` and `beta` particles are-
A magnetic needle suspended parallel to a magnetic field requires `sqrt3` J of work to turn it through `60^o`. The torque needed to maintain the needle in the position will be:
A man is watching two trains, one leaving and the other coming with equal speed of 4 m/s. If they sound their whistles each of frequency 240 Hz, the number of beats per sec heard by man will be equal to: (velocity of sound in air=320 m/s):
If the ratio of lengths, radii and Young’s modulus of steel and brass wires in the figure are a, b and c respectively, then the corresponding ratio of increase in their length would be:
A body of mass 2 kg is in influence a force which causes displacement in it given `x=t^2+4t`, metres where t is time. The work done by the force in 2 seconds is:
