**NEET Paper set 1**

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2

When the light of frequency 2_{v0} (where v0 is threshold frequency), is incident on a metal plate, the maximum velocity of electrons emitted is v_{1}. When the frequency of the incident radiation is increased to 5_{v0}, the maximum velocity of electrons emitted from the same plate is v_{2.} The ratio of v_{1 }to v_{2} is

3

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

4

The ratio of kinetic energy to the total energy of an electron in a Bohr orbit of the hydrogen atom, is

5

An astronomical refracting telescope will have large angular magnification and high angular resolution, when it has an objective lens of

6

In Young's double slit experiment the separation d between the slits is 2 mm, the wavelength ? 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 ? and D) the separation between the slits needs to be changed to

7

Unpolarised light is incident from air on a plane surface of a material of refractive index '?'. 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

8

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?

9

The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat absorbed by it, when it undergoes a change from state A to state B, is

10

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

11

A carbon resistor of (47 ± 4.7) k? is to be marked with rings of different colours for its identification. The colour code sequence will be

12

The efficiency of an ideal heat engine working between the freezing point and boiling point of water, is

13

At what temperature will the rms speed of oxygen molecules become just sufficient for escaping from the Earth's atmosphere?

(Given :

Mass of oxygen molecule (m) = 2.76 × 10^{–26} kg Boltzmann's constant kB = 1.38 × 10–23 JK^{-1})

14

The fundamental frequency in an open organ pipe is equal to the third harmonic of a closed organ pipe. If the length of the closed organ pipe is 20 cm, the length of the open organ pipe is