ECAT Pre Engineering Physics Chapter 19 MCQ Test With Answer

Top Scorers Of Physics ECAT Pre Engineering Chapter 19 Dawn of Modern Physics MCQ`s Test

Sr.#	Question	Answer
1	An inertial frame is that frame in which	A. a>0 B. a=0 C. a<0 D. none of these
2	An electron is accelerated through a potential difference of 50v. its de-Brogile wavelength is	A. 1.66 x 10^-29m B. 1.74 x 10^-10cm C. 17.4 x 10^-6m D. 1.74 x 10^-10m
3	Position was discovered by Carl Anderson in	A. 1920 B. 1925 C. 1928 D. 1932
4	The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes	A. 2 mo B. 1.67 mo C. 0.67 mo D. 2.67 mo
5	When a platinum wire is heated, it appears orange red at	A. 500°C B. 900°C C. 1100°C D. 1300°C
6	When platinum wire is heated, then at the temperature of 500 ^oC, it becomes:	A. Yellow B. Orange red C. Dull red D. White
7	The threshold frequency of sodium is 6 x 10⁶MHz. The cut-off wavelength for this metal will be	A. 500 m B. 500 nm C. 500 km D. 500 cm
8	When a platinum wire is heated, it appears dull red at about	A. 500°C B. 900°C C. 1100°C D. 1300°C
9	According to the special theory of relativity, a moving clock	A. runs faster B. runs slower C. neither runs faster nor slower D. all of these
10	If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers	A. larger B. shorter C. equal D. none of these