Recent questions tagged ncert

The direction of ray of light incident on a concave mirror is shown by PQ, while direction in which the ray would travel after reflection shown in this figure. marked 1,2,3 and 4. Which of the four rays shows the direction of reflected ray ?

asked Jun 15, 2016 by meena.p

1 answer

The phenomenon involved in the reflection of radio waves by ionosphere is similar to

asked Jun 15, 2016 by meena.p

1 answer

You are given four sources of light each one providing a light of a single colour - red, blue , green and yellow . Suppose the angle of refraction for a beam of yellow light corresponding to a particular angle of incident at an interface of two media is $90^{\circ}$ which of the following : Statement is correct if the source of yellow light is replaced with that of other lights without changing the angle incident ?

asked Jun 15, 2016 by meena.p

1 answer

A passenger in an aeroplane shall

asked Jun 15, 2016 by meena.p

1 answer

An object approaches a convergent lens from the left of the lens with a uniform speed 5 m/s and stops at the focus at the focus . The image

asked Jun 15, 2016 by meena.p

1 answer

when a low flying passes overhead , we sometimes notice a slight shaking of the picture on our TV screen . Suggest a possible explanation .

asked Jun 15, 2016 by meena.p

1 answer

A parallel beam of light of wave length 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen i m away . It is observed that the first minimum is at a distance of 2,5 nm from the center of the screen . Find the width of the slit .

asked Jun 15, 2016 by meena.p

1 answer

Two towers on top of two hills are 40 km apart. The line joining then passes 50 m above a hill halfway between the tower . What is the longest wavelength of radio waves , which can be sent between the towers with out appreciable diffraction effects ?

asked Jun 15, 2016 by meena.p

1 answer

Ray optics is based on the assumption that light travels in a straight line . Diffraction effects observed when light propagates through small apertures / silts or around small obstacles ) disprove this assumption , yet the ray optics assumption is so commonly used in understanding location and several other properties of image in optical instruments? what is the justification ?

asked Jun 15, 2016 by meena.p

1 answer

When a tiny circular is placed in the path of light from a distant source, a bright spot in seen at the center of the shadow of the obstacle . explain why ?

asked Jun 15, 2016 by meena.p

1 answer

Two students are separated by a 7 m partition wall in a room 10 m high . If both light and sound waves can bend round corners, how is it that the student are unable to see each other even through they can converse easily

asked Jun 15, 2016 by meena.p

1 answer

In what way diffraction from each slit related to interference pattern in a double slit experiment?

asked Jun 15, 2016 by meena.p

1 answer

In a single slit diffraction experiment, the width of the slit is made double the original width. How does this affect the size and intensity of the central diffraction band ?

asked Jun 15, 2016 by meena.p

1 answer

In a double slit experiment using light of wavelength $600\; nm$ , the angular width of a fringe formed on a distant screen is $0.1^{\circ}$ What is the spacing between the two slits ?

asked Jun 15, 2016 by meena.p

1 answer

For sound waves the Doppler formula the frequency shift differs slightly between the two situation (i) source at rest; observe moving (ii) source moving ; observing at rest . The exact Doppler formula for the case light waves in vacuum , are however strictly ideal for the two situation in case of light travelling in a medium ?

asked Jun 14, 2016 by meena.p

1 answer

Below are some of the factors which could possibly influence the speed of wave propagation. What are the factors which could possibly influence the speed of propagation of light ?

asked Jun 14, 2016 by meena.p

1 answer

Let us list some of the factors which could possibly influence the speed of wave propagation . (i) nature of source (ii) direction of propagation (iii) motion of source and /or observe (iv) wave length (v) internity of the wave on which of these factors if any does the speed of light in vaccum depend .

asked Jun 14, 2016 by meena.p

1 answer

Explain : how Newtons corpuscular theory predicts the speed of light in a medium , say water, to be greater than the speed of light in vacuum. Is the prediction confirmed by the experimental determination of speed of light in water ? If not , which alternative picture of light is consistent with experiment ?

asked Jun 14, 2016 by meena.p

1 answer

The $6563 A^{\circ} H_2$ line emitted by hydrogen in a star is found to be red shifted by $15^{\circ}$ , Estimate the speed with which the star is reading from earth .

asked Jun 14, 2016 by meena.p

1 answer

Estimate the distance for which ray is good approximation for an aperture of $4\;mm$ and wave length $400\;nm$

asked Jun 14, 2016 by meena.p

1 answer

Light of wave length $5000A^{\circ}$ falls on a reflecting surface . What are the wave length and frequency of the reflected light ? For what angle of incidence is the reflected ray normal to the incident ray ?

asked May 26, 2016 by meena.p

1 answer

A beam of light consisting of two wave length 650 nm and 520 nm, is used to obtain interference finger in a young's double slit experiment . What is the least distance from the central maximum ? Where the bright fringer due to both wavelength coincide ?

asked May 26, 2016 by meena.p

1 answer

A beam of light consisting of two wave length 650 nm and 520 nm, is used to obtain interference finger in a young's double slit experiment . Find the distance of the third bright fringe on the screen from the central maximum for wave length 650 nm

asked May 26, 2016 by meena.p

1 answer

In a double slit experiment, the angular width of a fringe is found to be $0.2 ^{\circ}$ on a screen placed 1 m away . The wave length of light used is 600 nm. What will be the angular width of the fringe if the entire experimental approaches is immerse in water ? Take refractive index of water to be 4/3 ?

asked May 26, 2016 by meena.p

1 answer

What is Brewster's angle for air to glass transition ?

asked May 26, 2016 by meena.p

1 answer

In Young's double slit experience using monochromatic light of wave length $\lambda$ , the intensity of light at a point on the screen where path different is $\lambda$ is k units. What is the intensity at a point where path different is $\large\frac{\lambda}{3}$

asked May 26, 2016 by meena.p

1 answer

In yang's double slit experiment , the slit are separated by $0.25$ mm and the screen is placed 1.4 m away. The distance the control bright fringe and the fourth bright fringe is measured to be 1.2 cm determine the wave length of light used in the experiment

asked May 26, 2016 by meena.p

1 answer

If the speed of light in glass independent of colors of light , If not which of the two colours, red and violet travels slower in a glass prism ?

asked May 26, 2016 by meena.p

1 answer

The refractive index of glass is 1.5 . What is the speed of light in glass ? (speed of light in vacuum is $3 \times 10^{8}m/s$)

asked May 26, 2016 by meena.p

1 answer

What is the shape of the wave front when the portion of the wavepool of light from a distant star is intercepted by earth

asked May 26, 2016 by meena.p

1 answer

what is the shape of the wave length in the light emerging out of a cave lens when a point source is placed at its focus

asked May 26, 2016 by meena.p

1 answer

What is the shape of the wave front in the light diverging from point source .

asked May 26, 2016 by meena.p

1 answer

Monochromatic light of wavelength $589\;nm$ is incident from air on a water surface. What is the wave length frequency and speed of reflected light ? $\mu=1.33$

asked May 26, 2016 by meena.p

1 answer

Monochromatic light of wavelength $589\;nm$ is incident from air on a water surface. What is the wave length frequency and speed of reflected light ? $\mu$ of water is 1.33

asked May 26, 2016 by meena.p

1 answer

Why does a convex lens of glass $\mu = 1.5 $ behave as a diverging lens when immersed in carbon sulfide of $\mu= 1.65$?

asked May 25, 2016 by meena.p

1 answer

A magician during a show makes a glass lens $\mu = 1.5 $ disappears in a trough of liquid . What is the refractive index of the liquid ? Is the liquid water ?

asked May 25, 2016 by meena.p

1 answer

The sun (diameter d ) subtends an angle $\theta$ radian at the pole of a concave mirror of focal length f. What is the diameter of the image of the sun formed by the mirror ?

asked May 25, 2016 by meena.p

1 answer

A ray of light is incident at an angle of $60^{\circ}$ on a horizontal plane mirror. Through what angle should the mirror be titled to make the reflected ray horizontal ?

asked May 25, 2016 by meena.p

1 answer

What focal length should the reading spectacles have for a person whose near point is 50 cm ?

asked May 25, 2016 by meena.p

1 answer

One face of a prism is silvered and if refracting angle $30^{\circ}$ and refracting index 1.414 is silvered . At what angle must a ray of light fall on the silvered surface so that after refraction into prism and reflection at the silvered surface it retrace the path ?

asked May 25, 2016 by meena.p

1 answer

A convex and concave mirror each of radius 10 cm are placed facing each other and 15 cm apart. A point object is placed midway between them . Find the position of the final image if the reflection takes place at the concave mirror and then at the convex mirror .

asked May 25, 2016 by meena.p

1 answer

A point source kept at a distance of 1000 m has an illumination I. To change the illumination to 16 I the new distance should be

asked May 25, 2016 by meena.p

1 answer

Magnification power of an astronomical telescope for normal vision with usual notation is

asked May 25, 2016 by meena.p

1 answer

An eye specialist prescribe spectacles having combination of convex lens of focal length 40 cm in contact with a concave lens of focal length 25 cm . The power of this lens combination , in dioptre.

asked May 25, 2016 by meena.p

1 answer

A source exits sound of frequency 600 Hz inside water. The frequency heard in air (velocity of sound in water 1500 m/s velocity of sand in air 300 m/s) will be

asked May 25, 2016 by meena.p

1 answer

A substance has a critical angle of $45^{\circ}$ for yellow light. What is its refractive index ?

asked May 25, 2016 by meena.p

1 answer

A thin convex lens of focal length 25 cm is cut into two pieces 0.5 cm above the principal axis . The top part is placed at $(0,0) $ and an object at $(-50 cm, 0)$. Find the coordinate axis ?

asked May 25, 2016 by meena.p

1 answer

For a glass prism $(\mu=\sqrt 3)$ the angle of minimum deviation is equal to the angle of the prism . Find the angle of the prism .

asked May 25, 2016 by meena.p

1 answer

The immiscible liquids of densities $d_1 > d_2 > d_3$ and refractive indices $\mu_1 > \mu_2 > \mu_3$ are put in a beaker . The height of each liquid column is $\large\frac{h}{3}$. A dot is made at the bottom of the beaker . For near normal vision, find the apparent depth of the dot .

asked May 25, 2016 by meena.p

1 answer

An unsymmetrical double convex thin lens, forms the image of a point object on its axis will the position of the image change in the lens is reversed ?

asked May 25, 2016 by meena.p

1 answer

Ask Questions, Get Answers