681 X-ray are________________? Physics Medium Full question → A of unknown nature B high energy electrons C high energy photons D radio isotopes
682 Hydrogen atom does not emit X-rays because _________________? Physics Medium Full question → A its energy levels are too close to each other B its energy levels are too far apart C it is too small in size D it has a single electron
683 Excited atoms return to their ground state in_______________? Physics Medium Full question → A 10-10s B 10-8s C 10-6s D 10-9s
684 In hydrogen spectrum which one of the following series lies in the ultraviolet region ? Physics Medium Full question → A Balmer series B Pfund series C Bracket series D Lymann series
685 Ratio of the weight of H-atom to that of an electron is approximately______________? Physics Medium Full question → A 18.336 B 1836 C 18360 D 183.6
686 Michelson calculated the speed of light using the instruments______________? Physics Medium Full question → A spectrometer B galvanometer C interferometer D none of these
687 The equation θ = 1.22 λ/D was devised by_______________? Physics Medium Full question → A Newton B Einstein C Raleigh D Planks
688 For a gas obeying Boyles law if the pressure is doubled the volume becomes________________? Physics Medium Full question → A double B one half C four times D one fourth
689 The area enclosed by the curve ABCDA for a Carnot heat engine represents the work done by Carnot engine_______________? Physics Medium Full question → A at any instant B averagely C during its operation D during one cycle
690 At what temperature is the Fahrenheit scale reading equal to twice that of the Celsius scale? Physics Medium Full question → A 460°C B 280°C C 360°C D 160°C
691 Standard condition STP refer to a gas at ___________________? Physics Medium Full question → A 76cm 0°C B 760mm 273K C 1atm 273K D all of the above
692 Which one is true for internal energy ? Physics Medium Full question → A It is sum of all forms of energies associated with molecules of a system B It is a state function of a system C It is proportional to transnational K.E of the molecules D All are correct
693 According to Pascals law the pressure of gas in a vessel is_____________? Physics Medium Full question → A Different in different direction B Same in all direction C Same only along opposite directions D Same only along normal directions
694 The size of one degree of Celsius is equal to_________________? Physics Medium Full question → A One degree of Fahrenheit scale B 1.8 degrees of Fahrenheit scale C 3.2 degrees of Fahrenheit scale D 2.12 degrees of Fahrenheit scale
695 The Fahrenheit and centigrade scales agree to________________? Physics Medium Full question → A 40 B 15.5 C 542 D 273
696 Normal human body temperature 98.6°F corresponds to______________? Physics Medium Full question → A 37°C B 42°C C 55°C D 410°C
697 Numerical value of Boltzmanns constant is______________? Physics Medium Full question → A 1.38×10-31JK-1 B 3.18×10-31JK-1 C 3.18×10-23JK-1 D 1.38×10-23JK-1
698 We prefer mercury as a thermometric substance because______________? Physics Medium Full question → A Over a wide range of temperature its expansion is uniform B It does not stick to thermometer glass C It opaque to light D All of above
699 In a clinical thermometer the mercury in the capillary tube does not contract once removed from the patient because_______________? Physics Medium Full question → A Mercury takes a long time to contract B The amount of mercury use is very small C The capillary tube has a small constriction near the bulb D The capillary tube is very narrow
700 Which one is not an example of adiabatic process ? Physics Medium Full question → A rapid escape of air from a burst tyre B rapid expansion of air C conversion of water into ice in refrigerator D cloud formation in the atmosphere