1 Crore+ students have signed up on EduRev. Have you? 
A device which converts electrical energy into mechanical energy is
According toMoseley's law, the frequency of a spectral line in X  ray spectrum varies as
A cell of e.m.f. E is connected with an external resistance R, then p.d. across cell is V. The internal resistance of cell will be
If sky wave with a frequency of 50 MHz is incident on Dregion at an angle of 30^{o}, then angle of refraction is
Given:
f = 50 MHz
The angle of incidence (I) = 30^{o}
Sin i = Sin r
r = 30^{o}
The resistance of a wire of iron is 10 ohms and temp. coefficient of resistivity is 5x10^{3}∕℃. At 20^{o}C it carries 30 milliamperes of current. Keeping constant potential difference between its ends, the temperature of the wire is raised to 120^{o}C. The current in milliamperes that flows in the wire is
A wire of resistance 1 Ω is stretched to double its length. The resistance will become
The wing span of an aeroplane is 36 m. If the plane is flying at 400 km/h, the e.m.f. induced between the wings tips is (assume V=4X10)
A cylinder of radius R and length L is placed in a uniform electric field E parallel to the cylinder axis, the total electric flux for the surface of the cylinder is
Total charge enclosed is zero
Two charges 10 C and + 10 C are placed 10cm apart. Potential at the centre of the line joining two charges is
What will be the ratio of de Broglie wavelengths of proton and αparticle of same energy
A body of capacity 4 μ F is charged to 80V and another body of capacity 6 μ F is charged to 30V. When they are connected the energy lost by 4 μ F is
A wire of radius r has resistance R. If it is stretched to a radius of 3r/4, its resistance becomes
Let L_{1} be the length and A_{1} the area of crosssection of the original wire and L_{2}, A_{2} be their values of the stretched wire
Since volume of the wire remains unchanged, we have
An electric dipole of dipole moment p is placed in uniform electric field of strength E. If θ is the angle between p and E, then potential energy of the dipole becomes maximum, when θ is
A capacitor of 10 μF charged up to 250 volts is connected in parallel with another capacitor of 5 μF charged up to 100 volts. The common potential is
Substances which have identical chemical properties but differ in atomic weight are called
The work function of a substance is 4.0 eV. The longest wavelength of light that can cause photoelectron emission from this substance is approximately
When plate voltage in diode valve is increased from 100 volt to 150 volt then plate current increases from 7.5 mA to 12 mA. The dynamic plate resistance will be
A prism of refractive index ' μ ' and angle 'A' is placed in the minimum deviation position. If the angle of minimum deviation is 'A', then the value of 'A' in terms of ' μ ' is
In a good conductor the energy gap between the conduction band and the valence band is
To make Ptype semiconductor, the impurity to be mixed with pure germanium will be
In forward bias the width of potential barrier in a pn junction diode
In Young's experiment of double slit, the intensity of central bright band is  times the individual intensities of the interfering waves
Two waves of intensities I and 4 I superimpose, then maximum and minimum intensities are
If a star is moving towards the earth, then the spectrum lines are shifted towards
1 videos3 docs73 tests

Use Code STAYHOME200 and get INR 200 additional OFF

Use Coupon Code 
1 videos3 docs73 tests









