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# Test: Modern Physics (Competition Level 2)

## 26 Questions MCQ Test Physics Class 12 | Test: Modern Physics (Competition Level 2)

Description
This mock test of Test: Modern Physics (Competition Level 2) for Class 12 helps you for every Class 12 entrance exam. This contains 26 Multiple Choice Questions for Class 12 Test: Modern Physics (Competition Level 2) (mcq) to study with solutions a complete question bank. The solved questions answers in this Test: Modern Physics (Competition Level 2) quiz give you a good mix of easy questions and tough questions. Class 12 students definitely take this Test: Modern Physics (Competition Level 2) exercise for a better result in the exam. You can find other Test: Modern Physics (Competition Level 2) extra questions, long questions & short questions for Class 12 on EduRev as well by searching above.
QUESTION: 1

Solution:
QUESTION: 2

### The frequency and the intensity of a beam of light falling on the surface of photoelectric material are increased by a factor of two (Treating efficiency of photoelectron generation as constant). This will :

Solution: QUESTION: 3

### Light coming from a discharge tube filled with hydrogen falls on the cathode of the photoelectric cell. The work function of the surface of cathode is 4eV. Which one of the following values of the anode voltage (in Volts) with respect to the cathode will likely to make the photo current zero.

Solution:
QUESTION: 4

Let K1 be the maximum kinetic energy of photoelectrons emitted by a light of wavelength l1 and K2 corresponding to l2. If l1 = 2l2, then :

Solution:
QUESTION: 5

In a photoelectric experiment, the potential difference V that must be maintained between the illuminated surface and the collector so as just to prevent any electron from reaching the collector is determined for different frequencies f of the incident illumination. The graph obtained is shown. The maximum kinetic energy of the electrons emitted at frequency f1 is Solution:
*Multiple options can be correct
QUESTION: 6

In photoelectric effect, stopping potential depends on

Solution:
*Multiple options can be correct
QUESTION: 7

In the experiment on photoelectric effect using light having frequency greater than the threshold frequency, the photocurrent will certainly increase when

Solution:
QUESTION: 8

Two electrons are moving with the same speed v. One electron enters a region of uniform electric field while the other enters a region of uniform magnetic field, then after sometime if the de-Broglie wavelengths of the two are l1 and l2 then :

Solution:
QUESTION: 9

An electron in hydrogen atom first jumps from second excited state to first excited state and then, from first excited state to ground state. Let the ratio of wavelength, momentum and energy of photons in the two cases by x, y and z, then select the wrong answers :

Solution:
QUESTION: 10

An electron is in an excited state in hydrogen-like atom. It has a total energy of –3.4 eV. If the kinetic energy of the electron is E and its de-Broglie wavelength is l, then

Solution:
*Multiple options can be correct
QUESTION: 11

A particular hydrogen like atom has its ground state binding "energy 122.4 eV. Its is in ground state. Then :

Solution:
*Multiple options can be correct
QUESTION: 12

The electron in a hydrogen atom makes a transition n1 ¾→ n2, where n1 & n2 are the principal quantum numbers of the two states. Assume the Bohr model to be valid. The time period of the electron in the initial state is eight times that in the final state. The possible values of n1 & n2 are :

Solution:
*Multiple options can be correct
QUESTION: 13

A beam of ultraviolet light of all wavelengths passes through hydrogen gas at room temperature, in the x-direction. Assume that all photons emitted due to electron transition inside the gas emerge in the y-direction. Let A and B denote the lights emerging from the gas in the x and y directions respectively.

Solution:
*Multiple options can be correct
QUESTION: 14

If radiation of allow wavelengths from ultraviolet to infrared is passed through hydrogen agas at room temperature, absorption lines will be observed in the :

Solution:
*Multiple options can be correct
QUESTION: 15

In the hydrogen atom, if the reference level of potential energy is assumed to be zero at the ground state level. Choose the incorrect statement.

Solution:
*Multiple options can be correct
QUESTION: 16

Statement-1: Figure shows graph of stopping potential and frequency of incident light in photoelectric effect. For values of frequency less than threshold frequecy (v0) stopping potential is negative. Statement-2 : Lower the value of frequency of incident light (for n > n0) the lower is the maxima of kinetic energy of emitted photoelectrons.

Solution:
*Multiple options can be correct
QUESTION: 17

Statement-1: In the process of photo electric emission, all the emitted photoelectrons have same K.E.

Statement-2: According to einstein's photo electric equation KEmax = hn – f.

Solution:
*Multiple options can be correct
QUESTION: 18

Statement-1: Work function of aluminum is 4.2 eV. If two photons each of energy 2.5 eV strikes on a piece of aluminum, the photo electric emission does not occur.

Statement-2: In photo electric effect a single photon interacts with a single electron and electron is emitted only if energy of each incident photon is greater then the work function.

Solution:
*Multiple options can be correct
QUESTION: 19

Statement-1: An electron and a proton are accelerated through the same potential difference. The deBroglie wavelength associated with the electron is longer.

Statement-2: De-Broglie wavelength associated with a moving particle is l = where, p is the linear momentum and both have same K.E.

Solution:
*Multiple options can be correct
QUESTION: 20

Statement-1: Two photons having equal wavelengths have equal linear momenta.

Statement-2: When light shows its photon character, each photon has a linear momentum p = .

Solution:
*Answer can only contain numeric values
QUESTION: 21

A parallel beam of uniform, monochromatic light of wavelength 2640 A has an intensity of 200 W/m2. The number of photons in 1 mm3 of this radiation are ...............

Solution:
QUESTION: 22

The total energy of the electron in the hydrogen atom in the ground state is -13.6 eV. Which of the following is its kinetic energy in the first excited state?

Solution:
*Answer can only contain numeric values
QUESTION: 23

When a monochromatic point source of light is at a distance of 0.2 m from a photoelectric cell, the cut off voltage and the saturation current are respectively 0.6 volt and 18.0 mA. If the same source is placed 0.6 m away from the photoelectric cell, then find

Q

the stopping potential

Solution:
*Answer can only contain numeric values
QUESTION: 24

When a monochromatic point source of light is at a distance of 0.2 m from a photoelectric cell, the cut off voltage and the saturation current are respectively 0.6 volt and 18.0 mA. If the same source is placed 0.6 m away from the photoelectric cell, then find

Q.

the saturation current

Solution:
*Answer can only contain numeric values
QUESTION: 25

An isolated metal body is illuminated with monochromatic light and is observed to become charged to a steady positive potential 1.0 V with respect to the surrounding. The work function of the metal is 3.0 eV. The frequency of the incident light is ___________________ eV.

Solution:
QUESTION: 26

663 mW of light from a 540 nm source is incident on the surface of a metal. If only 1 of each 5×109 incident photons in absorbed and causes an electron to be ejected from the surface, the total photocurrent in the circuit is ____________________.

Solution: