PPSC Physics Topic 7 Modern Physics With Answers

PPSC Physics Topic 7 Modern Physics

Sr. # Questions Answers Choice
1 When of the following radiations are not emitted by electron transitions in atoms. Visible rays Ultraviolet rays Infrared radiations Alpha particles
2 The path of electron in Rutherford atomic model according to classical theory a. Parabolic Straight line Spiral Circular
3 Alpha particles are Helium nuclei sodium nuclei Ioized nuclei Hydrogen nuclei
4 The ionization potential of hydrogen atom is. 10.2 V 13.6 V 12.97 V 27.2 V
5 Bohr's atomic model assumes Nucleus is of infinite mass and is at rest electron in a quantized orbit will not radiate energy Mass of electron remains the same All of the above
6 According to Max. Planck, energy is released or absorbed in discrete packets called. quanta Meson Energy shells Position
7 When a platinum wire is heated of 1600 oC, it becomes orange Cherry red Dull red White
8 At high temperature a body generally emits redactions of. Small wavelengths Long wavelengths Moderates wavelengths Zero wavelengths
9 Mass -energy relation means that the product of mass times the square of the speed of light must be equal to. Torque Momentum Energy Impulse
10 If an object moves with velocity of light the apparent mass of the object as compared to list original mass is greater Smaller Same zero
11 If an object moves with velocity of light the apparent length of the object moving the direction of motion becomes. Larger Smaller Zero Infinity
12 When an object moves with a very high speed the length in the direction of motion. Contracts Expands Remains the same Becomes infinity
13 The part of theory of relativity which deals with accelerated bodies is called. special theory of relativity General theory of relativity Lorentz's theory of relativity Galilean theory of relativity
14 Radius of the Bother's orbit is r the radius of second orbit will be. 2 r 3 r 4 r 8 r
15 Which term given below refers to the concept moving clocks run slower than clocks at rest w.r.t an observer. Simultaneously Mass variation time dilation Length contraction
16 Which of the following describes that the time interval between two events may be different in different of references Simullaneously Time dilation Length contraction Mass variation
17 Two electrons approach each other their relative velocity will be. Zero c c/2 Infinity
18 Special theory of relativity deals with the events in the frames of reference which move with constant. Time interval Acceleration Momentum space interval
19 A photon is chasing an electron, whose speed is 0.9 c What is their relative speed. 0.1 C C 0.8 C 0.9 C
20 At what speed the mass of a body will be doubled. 0.67 C 0.77 C 0.87 C 0.97 C
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