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| 1)The masses of three wires of copper are in the ratio 1:2:4 and their lenghts are in the ratio of 4:2:1. Then the ratio of their electrical resistances is.
64:8:1 16:4:2 8:2:1 16:8:2 None of the above |
| 2)The drift velocity of electrons in a copper wire is found to be 5 mm/s.If the radius of the wire is halved, keeping the same current the new drift velocity in mm/s is.
20 10 2.5 1.25 None of the above |
| 3)The velocity of a helium nucleus travelling in a curved path in a magnetic field is v/2.The velocity of a proton travelling in the same curved path in that magnetic field will be.
v 4v 2v v/4 None of the above |
| 4)In Young's double slit experiment two coherent sources of intensity ratio of 64:1,produce interference fringes. Caculate the ratio of maximum and minimum intensities.
49:81 81:49 9:7 7:9 None of the above |
| 5)Two slits separated by a distance of 1mm are illuminated with red light of wavelength 6.5 x 10^-7m. The interference fringes are observed on a screen placed 1m from the slits. The distance between 3rd dark fringe and 5th bright fringe is.
0.66 mm 3.25 mm 1.63 mm 4.8 mm None of the above |
| 6)The ratio of wavelength of two light waves are 2:5. The ratio of amount of scattering of two lights are.
2:5 5:2 (2)^4:(5)^4 (5)^4:(2)^4 None of the above |
| 7)The specific charge of a proton is 9.6 x 10^7 C/kg.Then the specific charge of an alpha particle is.
2.4 x 10^7 C/kg 3.84 x 10^8 C/kg 1.92 x 10^8 C/kg 4.8 x 10^7 C/kg None of the above |
| 8)The percentage contraction length of a rod as observed by an observer O at rest is 10%. The speed of the rod according to the observer O is.
0.435 c 0.19 c 0.87 c 0.38 c None of the above |
| 9)In asample of radioactive material ,what percentage of the initial number of active nuclei will decay during one mean life.
37% 63% 50% 69.3% None of the above |
| 10)The indicator in rador is
camera tube CRT a screen ionisation chamber None of the above |