Author: Science sangrah

Communication Systems Which frequency range is used for TV transmission ?  (A) 30 HZ – 300 Hz (B) 30 KHZ – 300 kHZ (C) 30 MHz – 300 MHz (D) 30 GHz – 300 GHZ  Answer : (C) 30 MHz – 300 MHz Sky wave communication is based upon :  (A) reflection by ionosphere (B) […]

Semiconductor Electronics Region without free electrons and holes in a p-n junction is (a) n-region (b) p-region (c) depletion region (d) none of these Answer: (c) depletion region Which of the following statements is incorrect for the depletion region of a diode? (a) There the mobile charges exist. (b) Equal number of holes and electrons […]

Nuclei Objective Questions An element A decays into an element C by a two step process A → B+ 2He4 and B → C + 2e–. Then, (a) A and C are isotopes (b) A and C are isobars (c) B and C are isotopes (d) A and B are isobars Answer: (a) A and C are […]

Atoms Objective Questions The first model of atom in 1898 was proposed by (a) Ernst Rutherford (b) Albert Einstein (c) J.J. Thomson (d) Niels Bohr Answer: (c) J.J. Thomson In Geiger-Marsden scattering experiment, the trajectory traced by an a-particle depends on (a) number of collision (b) number of scattered a-particles (c) impact parameter (d) none […]

Dual Nature of Radiation and Matter Objective Who established that electric charge is quantised? (a) J.J. Thomson (b) William Crookes (c) R.A. Millikan (d) Wilhelm Rontgen Answer: (c) R.A. Millikan Cathode rays were discovered by (a) Maxwell Clerk James (b) Heinrich Hertz (c) William Crookes (d) J.J. Thomson Answer: (c) William Crookes The minimum energy […]