Apparent Depth

Q.

What is the relation between wavelength and refractive index?

Q.

To a bird in air a fish in water appears to be 30cm from its surface if ^a​​​​​​u_{​​​​​w} =4/3 then the true depth of fish is:

30cm

40cm

45cm

None of these

Q.

What is the cause of advanced sunrise and delayed sunset?

Q.

The apparent depth of an object at the bottom of a tank filled with a liquid of refractive index $1.3$ is $7.7cm$. What is the actual depth of the liquid in the tank?

Q.

Name the phenomenon due to which a swimming pool appears less deep than it really is.

Q.

How does the diffraction band of blue light look in comparison with the red light?

1. No changes

2. Diffraction pattern becomes narrower

3. Diffraction pattern becomes broader

4. Diffraction pattern disappears

Q.

A rectangular slab of refractive index $\mu$ is placed over another slab of refractive index 3, both slabs being identical in dimensions. If a coin is placed below the lower slab, for what value of $\mu$ will the coin appear to be placed at the interface between the slabs when viewed from the top

1. 2.5

2. 1.8

3. 2

4. 1.5

Q. Question 4
You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in the table.

$\begin{array}{cccc}Materialmedium& Refractiveindex& Materialmedium& Refractiveindex\\ Air& 1.0003& CanadaBalsam& 1.53\\ Ice& 1.31& -& -\\ Water& 1.33& Rocksalt& 1.54\\ Alcohol& 1.36& -& -\\ Kerosene& 1.44& Carbondisulphide& 1.63\\ Fusedquartz& 1.46& Denseflintglass& 1.65\\ Turpentineoil& 1.47& Ruby& 1.71\\ Benzene& 1.50& Sapphire& 1.77\\ Crownglass& 1.52& Diamond& 2.42\end{array}$

Q.

A fish is looking at a 1.0 m high plant at the edge of a pond. Will the plant appear to the fish shorter or taller than its actual height? Draw a ray diagram to support your answer.

Q.

A fish is swimming in a river at a depth of 20 cm from the surface of the water. Refractive Index of water is $\frac{4}{3}$. Then the eagle flying above the water will see the fish at ___ .

Q. An object at the bottom of a beaker filled with a liquid up to height of 10 cm. If the refractive index of liquid w.r.t. air ( ^aµ_w ) is 4/3, find the apparent depth of the object.

Q. Why an object submerged in water appears to be more closer than it's real depth ?

Q.

A tank of water is viewed normally from above.
(a) State how does the depth of tank appear to change.
(b) Draw a labeled ray diagram to explain your answer.

Q.

A point object forms a real, enlarged image, in front of a concave mirror of curvature radius 40 cm. If the distance between the object and the image be 30 cm, then the object distance will be 30 cm.

1. 10 cm

2. 30 cm

Q.

Draw a ray diagram to show the appearance of a stick partially immersed in water. Explain your answer.

Q. Question 4
You are given kerosene, turpentine and water. In which of these does the light travel fastest? Use the information given in the table.

$\begin{array}{cccc}Materialmedium& Refractiveindex& Materialmedium& Refractiveindex\\ Air& 1.0003& CanadaBalsam& 1.53\\ Ice& 1.31& -& -\\ Water& 1.33& Rocksalt& 1.54\\ Alcohol& 1.36& -& -\\ Kerosene& 1.44& Carbondisulphide& 1.63\\ Fusedquartz& 1.46& Denseflintglass& 1.65\\ Turpentineoil& 1.47& Ruby& 1.71\\ Benzene& 1.50& Sapphire& 1.77\\ Crownglass& 1.52& Diamond& 2.42\end{array}$

Q.

A student puts his pencil into an empty trough and observes the pencil from the position as indicated in Fig. 4.41.

(i) What change will be observed in the appearance of the pencil when water is poured into the trough?

(ii) Name the phenomenon which accounts for the above-stated observation.

(iii) Complete the diagram showing how the student's eye sees the pencil through the water.

Q.

There is a black spot on a table. A glass slab of thickness 6 cm is placed on the table over the spot. The refractive index of glass is $\frac{3}{2}$. At what depth from the upper surface will the spot appear when viewed from above?

Q. Suppose refractive index $\mu$ is given as
$\mu =A+\frac{B}{{\lambda }^2}$
where A and B are constants and $\lambda$ is wavelength, then dimensions of B are same as that of

1. Wavelength
2. Volume
3. Pressure
4. Area

Q. An object $10cm$ in height is placed at a distance of $36cm$ from a concave mirror. If the image is formed at a distance of $18cm$ in front of the mirror, find the height of image.

Q. A coin is placed at the bottom of a beaker containing water (refractive index $=4/3$) to a depth of $12cm$. By what height the coin appears to be raised when seen from vertically above?

1. $9cm$
2. $16cm$
3. $3cm$
4. $4cm$

Q.

How much water should be filled in a container 21 cm in height, so that it appears half filled when viewed from the top of the container? (Given that ${}_{\alpha }{\mu }_{\omega }=\frac{4}{3}$)

1. 8.0 cm
2. 10.5 cm
3. 12.0 cm
4. None of the above

Q.

How much water should be filled in a container 21 cm in height, so that it appears half filled when viewed from the top of the container (given that ${}^a{\mu }_w=\frac{4}{3}$

1. 10.5 cm

2. 12.0 cm

3. 8.0 cm

4. None of the above

Q.

A rectangular tank of depth $8$ metres is full of water $\mu =\frac{4}{3}$ then, the bottom is seen at a depth of___metres.

Q. In a vessel of 21 cm upto what height the water should be filled so that now it appears to be half filled if viewed from the top.( Take refractive index of water =4/3 )

Q.

A plane mirror is placed at the bottom of a tank containing a liquid of refractive index $\mu$. P is a small object at a height h above the mirror. An observer O vertically above P above the liquid level sees P and its image in the mirror. The apparent distance between these two will be:

1. $\frac{\text{2h}}{\mu -1}$

2. $2\mu \text{h}$

3. $\frac{\text{2h}}{\mu }$

4. $\text{h}(1+\frac{1}{\mu })$

Q. A fish looks upward at an unobstructed overcast sky. What total angle does the sky appear to subtend? (Take refractive index of water as $\sqrt{2})$.

1. ${180}^{\circ }$
2. ${90}^{\circ }$
3. ${75}^{\circ }$
4. ${60}^{\circ }$

Q. Consider the situatuion shown in figure. A plane mirror is fixed at a height h above the bottom of a beaker containing water (refractive index $\mu$ ) up to a height d. Find the position of the image of the bottom formed by the mirror.

1. $h-d+\frac{d}{\mu }.$
2. $h+d+\frac{d}{\mu }.$
3. $h-d-\frac{d}{\mu }.$
4. $d+\frac{d}{\mu }.$

Q.

A coin is kept at bottom of an empty beaker. A traveling microscope is focussed on the coin from the top, now water is poured into beaker up to a height of $10cm$. By what distance and in which direction should the microscope be moved to bring the coin again in focus

1. 10 cm upward

2. 2.5 cm upwards

3. 10 cm downward

4. 2.5 cm downwards

Q. The refractive index of air with respect to glass is expressed as ${}_g{\mu }_a=\frac{\sin r}{\sin i}$. If angle $r={90}^o$, what is the corresponding angle $i$ called?

1. refracted angle
2. reflected angle
3. normal angle
4. Critical angle