ECAT Pre Computer Science Chapter 20 MCQ Test With Answer

Top Scorers Of ECAT Physics Chapter 20 Atomic Spectra MCQ`s Test

Sr.#	Question	Answer
1	The lasing or active medium in He-Ne laser discharge tube is:	A. Nitrogen B. Helium C. Hydrogen D. Neon
2	If the distance between two charges is doubled,the force between them will become:	A. Double B. Half C. One third D. One fourth
3	By CAT scans, we can detect the density difference of the order of:	A. 1% B. 20% C. 30% D. 50%
4	Atoms of hydrogen gas can be excited by passing electric current through it when the gas is filled into the discharge tube at a pressure which is	A. Less than atmospheric pressure B. Much less than atmospheric pressure C. Greater than atmospheric pressure D. Much greater than atmospheric pressure
5	Balmer series was identified in:	A. 1685 B. 1785 C. 1885 D. 1985
6	Selenium is:	A. An insulator B. A conductor C. Both A and B D. Excellent conductor
7	X-rays produced in a tube operating at 10⁵V. The speed of X-rays produced is	A. 3 x 10⁸m/s B. 3.1 x 10⁸m/s C. 2.8 x 10⁸m/s D. 1.88 x 10⁸m/s
8	The He-Ne laser discharge tube is filled with:	A. 85% He B. 15% He C. 50% He D. 60% He
9	X-rays can penetrate in a solid matte through a distance of several:	A. Kilo metres B. Metres C. Centimeters D. A few angstroms
10	The range of wavelengths of colurs in the visible colours is	A. 140 nm to 456 nm B. 10 nm to 56 nm C. 410 nm to 656 nm D. 910 nm to 956 nm