Physics 299 Questions Ask question Search Order By: ActiveCategoryClear Filter 1 Votes 1 Ans In a ideal transformer, the turns ratio N p /N s = 1/ 2 . The ratio V s : V p 𝑉 𝑠 : 𝑉 𝑝 is equal to (the symbols carry their usual meaning) : 92 viewsAditya Bhatt Changed status to publish 23 August 2024EducationPhysics 1 Votes 1 Ans A bob is whirled in a horizontal plane by means of a string with an initial speed of ω rpm. The tension in the string is T. If speed becomes 2 ω while keeping the same radius, the tension in the string becomes : (1) T (2) 4T (3) T/ 4 (4) √ 2 T 92 viewsAditya Bhatt Changed status to publish 22 August 2024EducationPhysics 1 Votes 1 Ans If represents the motion of a particle executing simple harmonic motion the amplitude and time period of motion, respectively, are (1) 5 cm, 2 s (2) 5 m, 2 s (3) 5 cm, 1 s (4) 5 m, 1 s 96 viewsAditya Bhatt Changed status to publish 22 August 2024EducationPhysics 1 Votes 1 Ans Given below are two statements: Statement I Atoms are electrically neutral as they contain equal number of positive and negative charges. Statement II Atoms of each element are stable and emit their characteristic spectrum. In the light of the above statements, choose the most appropriate answer from the options given below. (1) Both Statement I and Statement II are correct (2) Both Statement I and Statement II are incorrect (3) Statement I is correct but Statement II is incorrect (4) Statement I is incorrect but Statement II is correct 82 viewsAditya Bhatt Changed status to publish 22 August 2024EducationPhysics 1 Votes 1 Ans Average velocity of a particle executing SHM in one complete vibration is : 126 viewsAditya Bhatt Changed status to publish 22 August 2024EducationPhysics 0 Votes 0 Ans why the newton second law is called real law 72 viewsSumit Joshi Asked question 11 August 2024EducationPhysics 0 Votes 0 Ans In the combination of the following gates the output Y can be written in terms of inputs A and B as 88 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans In a PN junction diode change in temperature due to heating (1) Does not affect resistance of p-n junction (2) Affects only forward resistance (3) Affects only reverse resistance (4) Affects the overall V – I characteristics of p-n junction 76 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans In the circuit shown in the figure the input voltage Vi is 20 V, VBE = 0 and VCE = 0. The values of IB, IC and β are given by 87 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans When the light of frequency 2v0 (where v0 is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v1. When the frequency of the incident radiation is increased to 5v0, the maximum velocity of electrons emitted from the same plate is v2. The ratio of v1 to v2 is (1) 4 : 1 (2) 1 : 4 (3) 1 : 2 (4) 2 : 1 83 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans For a radioactive material half life is 10 minutes. If initially there are 600 number of nuclei, the time taken (in minutes) for the disintegration of 450 nuclei is (1) 30 (2) 10 (3) 20 (4) 15 70 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans An electron of mass m with an initial velocity 0 V Viˆ (V0 > 0) enters an electric field 0 E –E iˆ (E0 = constant > 0) at t = 0. If 0 is its de-Broglie wavelength initially, then its de-Broglie wavelength at time t i 80 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom, is (1) 2 : –1 (2) 1 : –1 (3) 1 : 1 (4) 1 : –2 91 viewsAditya Bhatt Changed status to publish 4 May 2024EducationPhysics 0 Votes 0 Ans An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of (1) Large focal length and large diameter (2) Large focal length and small diameter (3) Small focal length and large diameter (4) Small focal length and small diameter 90 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 0 Votes 0 Ans In Youngs double slit experiment the separation d between the slits is 2 mm, the wavelength λ of the light used is 5896 Å and distance D between the screen and slits is 100 cm. It is found that the angular width of the fringes is 0.20°. To increase the fringe angular width to 0.21° (with same λ and D) the separation between the slits needs to be changed to (1) 2.1 mm (2) 1.9 mm (3) 1.8 mm (4) 1.7 mm 85 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 0 Votes 0 Ans Unpolarised light is incident from air on a plane surface of a material of refractive index ‘μ’. At a particular angle of incidence ‘i’, it is found that the reflected and refracted rays are perpendicular to each other. Which of the following options is correct for this situation? 81 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 0 Votes 0 Ans A battery consists of a variable number n of identical cells (having internal resistance ‘r’ each) which are connected in series. The terminals of the battery are short-circuited and the current I is measured. Which of the graphs shows the correct relationship between I and n? 79 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 0 Votes 0 Ans A set of n equal resistors of value R each are connected in series to a battery of emf ‘E’ and internal resistance ‘R’. The current drawn is I. Now, the ‘n’ resistors are connected in parallel to the same battery. Then the current drawn from battery becomes 10 I. The value of ‘n’ is (1) 20 (2) 11 (3) 10 (4) 9 84 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 1 Votes 0 Ans The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is (1) 6.25% (2) 20% (3) 26.8% (4) 12.5% 86 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 0 Votes 0 Ans The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is (1) 6.25% (2) 20% (3) 26.8% (4) 12.5% 86 viewsAditya Bhatt Changed status to publish 3 May 2024EducationPhysics 1 2 3 … 14 15 Next »
