Intensity Explanation in YDSE

Q.

Two coherent monochromatic beams of intensities $I$ and $4I$ respectively are superposed. The ration of the maximum and minimum intensities in the resulting pattern is

1. $5:3$

2. $3:1$

3. $4:1$

4. $9:1$

Q.

In Youngs double-slit experiment, the angular width of a fringe formed on a distant screen is 1 degree. The wavelength of light used is 6000 Armstrong. What is the spacing between the slits?

Q. In a young’s double slit experiment the resultant intensity at a point on the screen with two sources with intensities 2I and 8I is 14I. Calculate the phase difference between the two sources.

1. ${40}^{\circ }$
2. ${50}^{\circ }$
3. ${60}^{\circ }$
4. ${90}^{\circ }$

Q.

In Young double slit experiment if the maximum intensity of light is $I_{max}$ then the intensity at path difference $\frac{\lambda }{2}$
will be)

1. $I_{max}$
2. $\frac{I_{max}}{2}$
3. $\frac{I_{max}}{4}$
4. $zero$

Q. In the young’s double slit experiment, the slit widths are in the ratio of 9:1. The ratio of the intensities at the maxima and minima will be

1. 3 : 1
2. 1 : 3
3. 1 : 4
4. 4 :1

Q.

Two coherent monochromatic beams of intensities $l$ and $4l$ respectively are superposed. The maximum and minimum intensities in the resulting pattern are:

1. $5I,2I$

2. $9I,I$

3. $4I,3I$

4. $5I,I$

Q.

In Young double slit experiment if the maximum intensity of light is $I_{max}$ then the intensity at path difference $\frac{\lambda }{2}$
will be)

1. $I_{max}$
2. $\frac{I_{max}}{2}$
3. $\frac{I_{max}}{4}$
4. $zero$

Q. Two identical, photocathodes receive light of frequencies $f_1$ and $f_2$. If the velocities of the photo electrons (of mass m) coming out are respectively $v_1$ and $v_2$, then (where the symbols have their usual meaning)

1. $v_1^2-v_2^2=\frac{2h}{m}(f_1-f_2)$
2. $v_1-v_2={\left(\frac{2h}{m}\right(f_1-f_2\left)\right)}^{\frac{1}{2}}$
3. $v_1+v_2={\left(\frac{2h}{m}\right(f_1+f_2\left)\right)}^{\frac{1}{2}}$
   
   
4. $v_1^2+v_2^2=\frac{2h}{m}(f_1+f_2)$

Q. With Young's two slit arrangement, the distance between the slits is 1 mm. The distance between the slits and the screen is one metre. The two slits are equally illuminated with light of wavelength $6000\dot{A}$. Then the minimum distance from the central maximum to a point where the intensity is half of the maximum is:

1. 0.6 mm
2. 0.3 mm
3. 0.15 mm
4. 2.4 mm

Q.

A ray of light of intensity I is incident on a parallel glass-slab at a point A as shown in fig. It undergoes partial reflection and refraction. At each reflection 25% of incident energy is reflected. The rays AB and A'B' undergo interference. The ratio is

[IIT 1990]

1. 4 : 1

2. 8 : 1

3. 7 : 1

4. 49 : 1

Q. The speed of electromagnetic wave in a medium whose dielectric constant is $2.25$ and relative permeability is $4$, is equal to

1. $0.5\times {10}^8\text{m/s}$
2. $0.25\times {10}^8\text{m/s}$
3. $0.75\times {10}^8\text{m/s}$
4. $1\times {10}^8\text{m/s}$

Q. The equation of two light waves are $y_1=6cos\omega t,y_2=8cos(\omega t+\varphi )$ the ratio of maximum to minimum intensities produced by the superposition of these wave will be

1. 49 :1
2. 1 : 49
3. 1 : 7
4. 7: 1

Q.

Two audio speakers are kept some distance apart and are driven by the same amplifier system. A person is sitting at a place 6.0 m from one of the speakers and 6.4 m from the other. If the sound signal is continuously varied from 500 Hz to 5000 Hz, what are the frequencies for which there is a destructive interference at the place of the listener? Speed of sound in air = $320\frac{m}{s}$.

1. 1.2, 2, 2.8, 3.6, 4.4 KHz

2. 1.2, 3.6 KHz

3. 1.2, 2.4, 3.6, 4.8 KHz

4. None of these

Q. The equation of two light waves are $y_1=6cos\omega t,y_2=8cos(\omega t+\varphi )$ the ratio of maximum to minimum intensities produced by the superposition of these wave will be

1. 49 :1
2. 1 : 49
3. 1 : 7
4. 7: 1

Q. The speed of electromagnetic wave in a medium whose dielectric constant is $2.25$ and relative permeability is $4$, is equal to

1. $0.25\times {10}^8\text{m/s}$
2. $0.75\times {10}^8\text{m/s}$
3. $1\times {10}^8\text{m/s}$
4. $0.5\times {10}^8\text{m/s}$

Q. The intensity ratio $\frac{I_1}{I_2}$ of the two interfering sources in Young's experiment is 4. The ratio $\frac{I_{max}}{I_{min}}$ is:

1. 4 : 1
2. 2 : 1
3. 3 : 1
4. 9 : 1

Q.

Figure here shows P and Q as two equally intense coherent sources emitting radiations of wavelength 20 m. The separation PQ is 5.0 m and phase of P is ahead of the phase of Q by ${90}^{\circ }$. A, B and C are three distant points of observation equidistant from the midpoint of PQ. The intensity of radiations at A, B, C will bear the ratio

[NSEP 1994]

1. 0 : 1 : 4

2. 4 : 1 : 0

3. 0 : 1 : 2

4. 2 : 1 : 0

Q. The intensities of two light sources are I and 9I respectively. If the phase difference between the waves emitted by them is $\pi$, then the resultant intensity at the point of observation will be

1. 3I
2. 4I
3. 10I
4. 82I