The anode voltage of a photocell is kept fixed. The wavelength
of the light falling on the cathode is gradually changed. The plate current I of the photocell varies as follows
The threshold frequency for a metallic surface corresponds to an energy of 6.2 eV, and the stopping potential for a radiation incident on this surface 5 V. Where the incident radiation lies?
What is the time by a photoelectron to come out after the photon strikes approximately?
If the kinetic energy of a free electron doubles, its de Broglie wavelength changes by the factor
A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed (1/2) m away, the number of electrons emitted by photocathode would
Explain Skull
Explain APPENDICULAR SKELETOM ?
AXIAL SKELETON
Types of HUMAN SKELETAL SYSTEM
Explain HUMAN SKELETAL SYSTEM
A charged oil drop is suspended in a uniform field of 3 × 104 V/m so that it neither falls nor rises. What will be the charge on the drop?
Note: mass of the charge = 9.9 × 10-15 kg and g = 10 m/s2
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
According to Einstein’s photoelectric equation, the plot of the kinetic energy of the emitted photo electrons from a metal vs the frequency, of the incident radiation gives a straight line whose slope
Two identical photocathodes receive light of frequencies f1 and f2. If the velocities of the photoelectrons (of mass m) coming out are respectively v1 and v2, then
Sodium and copper have work functions 2.3 eV and 4.5 eV respectively. Then what will be the ratio of the wavelengths?
The rms value of the electric field of the light coming from the sun is 720 N/C. The average total energy density of the electromagnetic wave is
An electromagnetic wave of frequency 
= 3.0 MHz passes from vacuum into a dielectric medium with permittivity 
= 4.0. Then
Consider telecommunication through optical fibres. Which of the following statements is not true?
find the point on the curve y*y = 4x which is nearest to the point (2, -8)?
Electromagnetic waves are transverse in nature is evident by
Infrared radiation is detected by
In a Young’s double slit experiment the intensity at a point where the path difference is 
/6( being the wavelength of light used) is I. If I0 denotes the maximum intensity, I / I0 is equal to
Two point white dots are 1 mm apart on a black paper. They are viewed by eye of pupil diameter 3 mm. Approximately, what is the maximum distance at which these dots can be resolved by the eye? [Note: wavelength of light = 500 nm]
When an unpolarized light of intensity I0 is incident on a polarizing sheet, the intensity of the light which does not get transmitted is
If I0 is the intensity of the principal maximum in the single slit diffraction pattern, then what will be its intensity when the slit width is doubled?
The area bounded by the x-axis, the curve y = f(x) and the lines x=1,x=b,is equal to 
for all b>1,then f(x) is
The non-zero vectors are a , b and c are related by a = 8b and c=–7b.Then the angle between a and c
The distance between two points P and Q is d and the length of their projections of PQ on the co-ordinate planes are
d1 ,d2 ,d3 .Then d2 +d2 +d2 =kd2 where‘k’is
The interval in which the function 
is decreasing is?
Let S be a finite set containing n elements. Then the total number of binary operations on S is:
An equation of the plane passing through the points (3,2,–1),(3,4,2)and(7,0,6) is 5x+3y–2z= 
,where is
A stone is dropped into a quiet lake and waves move in a circle at a speed of 3.5 cm/sec. At the instant when the radius of the circular wave is 7.5 cm. How fast is the enclosed area increasing?
A dice is tossed 5 times. Getting an odd number is considered a success. Then the variance of distribution of success is
Total number of possible matrices of order 3 × 3 with each entry 2or 0 is
A drunken man takes a step forward with probability 0.4 and backwards with probability 0.6. Find the probability that at the end of eleven steps, he is one step away from the starting point.
The resistance of 0.01 N solution of an electrolyte was found to be 220 ohm at 298 K using a conductivity cell with a cell constant of 0.88cm–1. The value of equivalent conductance of solution is –
Though the five d-orbitals are degenerate, the first four d-orbitals are similar to each other in shape whereas the fifth d-orbital is different from others. What is the designation of the fifth orbital?
How many P–H and O–H bonds respectively, are present in 
molecule?
The correct order of boiling points of 2, 2-dimethylpropane, 2-methylbutane and n-pentane is
The half life of a first order reaction is 10 min. If initial amount is 0.08 mol L-1 and concentration at some instant is 0.01 mol L-1. What is the time elapsed ?
Given the molecular formula of the hexa-coordinated complexes (i) CoCl3.6NH3, (ii) CoCl3.5NH3, (iii) CoCl3.4NH3 If the number of co-ordinated NH3 molecules in (i), (ii) and (iii) respectively are 6, 5, 4, the primary valencies in (i), (ii) and (iii) are :
A white sodium salt dissolves readily in water to give a solution which is neutral to litmus. When silver nitrate solution is added to the solution, a white precipitate is obtained which does not dissolve in dil. HNO3. The anion could be
Which one of the alkali metals, forms only, the normal oxide, M2O on heating in air ?
If the solutions of NaCl and NaNO3 are mixed in one beaker and the temperature adjusted to 383° K, the contents of the beaker will most likely:
Moissan boron is
An ‘fcc’ in a unit cell of aluminium contains the equivalent of how many atoms ?
A fire of lithium, sodium and potassium can be extinguished by