Physics Test 288

Result

Physics Test 288

Score
-
out of -
Rank
-
out of -

TIME Taken - -

Weekly Quiz Competition

Question 1
4 / -1

An electron moves in a magnetic field of 6 × 10⁻⁴ T with speed 3 × 10⁷ m/s perpendicular to the field. What is its radius of motion? (take mass of electron = 9 × 10⁻³¹ kg, charge = 1.6 × 10⁻¹⁹ C)

A
28 cm

B
2.8 cm

C
0.28 cm

D
28 m

Solution
Question 2
4 / -1

The process where a heavy nucleus splits into two or more lighter nuclei is called nuclear fission. This process releases energy primarily because the fission fragments have:

A
a higher number of total nucleons.

B
a much greater total mass than the original nucleus.

C
lower binding energy per nucleon than the original heavy nucleus.

D
higher binding energy per nucleon than the original heavy nucleus.

Solution

Nuclear fission releases energy because the resulting fission fragments are more stable than the original heavy nucleus.

Stability is related to the binding energy per nucleon; nuclei with a higher binding energy per nucleon are more stable.

The heavy nucleus (like uranium) has a lower binding energy per nucleon compared to the medium-sized nuclei (fission fragments) it splits into.

This difference in binding energy is released as kinetic energy of the fragments and other forms of energy.
Question 3
4 / -1

In accordance with the Bohr's model, find the quantum number that characterises the earth's revolution around the sun in an orbit of radius 1.5 × 10¹¹ m with orbital speed 3 × 10⁴ m/s. (Mass of earth = 6.0 × 10²⁴ kg. .)

A
2.56 × 10⁷²

B
5.1 × 10⁷⁶

C
3 × 10⁷⁶

D
2.56 × 10⁷⁴

Solution
Question 4
4 / -1

A plane glass plate is placed over various coloured letters (violet, green, yellow, red). The letter which appears to raise more is

A
Red

B
Yellow

C
Green

D
Violet

Solution

The apparent shift in the position of an object viewed through a glass plate is given by the formula:
Question 5
4 / -1

A
15

B
3

C
12

D
6

Solution
Question 6
4 / -1

In the photoelectric effect, for electrons to be ejected from a metal surface, the incident light must have a certain minimum value of which of the following properties?

A
Wavelength

B
Amplitude

C
Frequency

D
Angle of incidence

Solution
Question 7
4 / -1

The escape velocity of a sphere of mass m is given by ( G= universal gravitational constant, M_e= mass of earth and R_e= radius of earth):

A

B

C

D

Solution

Using the conservation of energy on the surface of earth and at infinity (where kinetic and potential energy will be zero), it can be shown that escape velocity has the formula:
Question 8
4 / -1

The work function of a metal surface is 2.0 eV . If light of wavelength 310 nm is incident on the surface, what is the maximum kinetic energy of the emitted photoelectrons? (Use hc = 1240eV ⋅ nm )

A
1.0e V

B
2.0e V

C
3.0e V

D
4.0e V

Solution
Question 9
4 / -1

A

B

C

D

Solution

The magnitude of a vector in three dimensions is given by the square root of the sum of the squares of its components:
Question 10
4 / -1

A

B

C

D

Solution