Modern Physics - TRB Physics Study Materials

SI NO.	QUESTIONS	ANSWERS
1.	The direction of deflection of positive rays is opposite to that?	Cathode rays
2.	The Thomson method when no electric or magnetic field is applied the positive ion strikes the screen at ‘0’ this is called?	Undeflected spot
3.	Aston’s mass spectrograph is used to?	Detection to isotopes
4.	Velocity selector is the instrument which inside?	Bainbridge’s mass
5.	The difference between the experimentally measured mass of isotope and its mass number is known as?	Mass defect
6.	The intensity of X-rays depends on?	Number of electrons striking the target
7.	In a tetragonal lattice a=b=0.25 nm and c=0.18 nm, deduce the lattice spacing’s between (111) planes?	0.126 nm
8.	The x-ray beam has been diffracted from various crystal planes, these spots are known as?	Laue spots
9.	Packing fraction for polonium is?	0.52
10.	According to Mosley’s law atomic number is the?	Fundamental property of element
11.	The change of wavelength in Compton effect is due to ?	Loss of energy of incident x-rays
12.	Lattice + Basis =?	Crystal structure
13.	Aprimitive cell is a type of?	Unit cell
14.	The angle of rotation is 360/n the axis is called?	n-fold
15.	The co-ordination number of fcc lattice is?	12
16.	A plan have intercepts 4, 1, 2 what are the miller indices?	142
17.	Find the miller indices for the intercepts 3a : 4b on the x and y axes and are parallel to the ‘Z’ axis?	(430)
18.	The process of emission of electrons from a metal plate when illuminated by light of suitable  wave length is called?	Photo electric effect
19.	Photo-Particle must be?	Negatively charged
20	At threshold frequently the K.E of photo electrons is?	Zero
21	Millikan’s experiment is based on?	Stopping potential
22	The cell which is used for reproduction of sound from photo – films is?	Photo emissive
23	Photo – Multiplier is based on the principle of?	Secondary emission
24	The nucleus of the atom was discovered by?	Rutherford
25	An electron cannot revolve round the nucleus in all possible orbits, this was suggested by?	Classical theory