ECAT Physics Online Test With Answers

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ECAT Physics Online Test

Sr. # Questions Answers Choice
1 The energy of photon 'E' is proported to The magnetic field H The electric field E Both the electric and magnetic field H and E Frequency
2 The energy of a photon is represented by h/c<sup>2</sup> h/T hc<sup>2</sup> hf/c<sup>2</sup>
3 According to the Max plank, energy is redialed or absorbed in discrete packets continuous waves either of them none of these
4 Max plank founded a mathematical model resulting in an equation that describes the shape of observed black body radiation curves exactly, in 1890 1895 1900 1905
5 The value of the Stephen's constant for black body radiations is given by 5.6 x 10<sup>8</sup>Wm<sup>-2</sup>K<sup>-4</sup> 5.67 x 10<sup>-8</sup>Wm<sup>-2</sup>K<sup>-4</sup> 2.9 x 10<sup>-3</sup>mK 2.9 x 10<sup>3</sup>mK
6 The Stephen-Boltzmann law for the black body radiation is given by E = T<sup>2</sup> E = -T<sup>2</sup> E = T<sup>4</sup> E = -T<sup>4</sup>
7 The inside cavity of the black body is painted white painted silver blackened with soot painted red
8 A black body is an ideal absorber an ideal radiator both of them none of them
9 When a platinum wire is heated, it appears white at 1600<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 900<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 1100<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 1300<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span>
10 When platinum wire is heated, it appears cherry red at 1600<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 900<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 1100<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 1300<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span>
11 When a platinum wire is heated, it appears yellow at 1600°C 900°C 1100°C 1300°C
12 When a platinum wire is heated, it appears orange red at 500<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 900<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 1100<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span> 1300<span style="color: rgb(84, 84, 84); font-family: arial, sans-serif; font-size: small;">°C</span>
13 When a platinum wire is heated, it appears dull red at about 500°C 900°C 1100°C 1300°C
14 A high temperature, the proportion of shorter wavelengths radiation, emitted by the body decreases first increases then decreases increases any one of them
15 At the temperature, a body emits radiation which is principally of long wavelengths in the visible region of long wavelengths in the invisible infrared region of short wavelength in invisible ultraviolet region none of these
16 According to the special theory of relativity, a moving clock runs faster runs slower neither runs faster nor slower all of these
17 Newton's law of motion do not hold in an accelerated frame of reference an unaccelerated frame of reference both of these none of these
18 The location and speed anywhere on earth can now be determined using relativistic effects by NAVISTAR to an accuracy of 2 cm/s 20 cm/s 200 cm/s 2000 cm/s
19 According to the special theory of relativity mass and energy are same entities mass and energy are same entities but interconverible mass and energy are different entities but interconverible mass and energy are different entities but non-interconveritble
20 The mass of an object will be doubled at speed 1.6 x 10<sup>8</sup>ms<sup>-1</sup> 2.6 X 10<sup>8</sup>ms<sup>-1</sup> 2.6 x 10<sup>7</sup>ms<sup>-1</sup> 2.6 x 10<sup>9</sup>ms<sup>-1</sup>
21 The mass 'm' of a body moving at 0.8 c (whose rest mass is mo) becomes 2 mo 1.67 mo 0.67 mo 2.67 mo
22 The Einstein's changes in length, mass and time are not observed in common life because We dont observer then seriously The masses are too large Their speed is too small than the speed of right All of the above
23 If a body reaches a speed equal to the speed of light, then its mass will became zero very small infinity none of these
24 If a material object moves with the speed of light 'C' its mass becomes Equal to its rest mass Four times of its rest mass Double of its rest mass Infinite
25 Which one of the following physical quantities changes with relativistic speed Length Mass Time All of the above
26 According to Einstein, with the great increase in the speed of the body, the relativistic mass of the body Remains constant Decreases Increases to infinity Reduced to zero
27 A bar 1.0 m in length and located along x-axix moves with a speed of 0.75 c with respect to a stationary observer. The length of the bar as measured by the stationary observer is 1.66 m 1.0 m 0.66 m 2.66 m
28 If you are moving at relativistic speed between two points that are a fixed distance apart, then the distance between the two points appers larger shorter equal none of these
29 According to Einstein, with the great increase in the speed of the body the relativistic length of the body Remains constant Decreases Increases Reduces to zero
30 The length contraction happens only Opposite to the direction of motion along the direction of motion perpendicular to the direction of motion In any direction
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