Answer
Verified
381k+ views
Hint: A lens is a piece of transparent glass which is bounded by two surfaces out of which at least one surface is spherical. Refraction is the bending of light when it obliquely travels from one medium to another medium. Here the power of combination of lenses is applied.
Complete step by step answer:
From the question, convex lenses and concave lenses are $0.75{\text{ m}}$ apart.
Therefore, from the power of combination of lenses.
$\dfrac{1}{f} = \dfrac{1}{{{f_1}}} + \dfrac{1}{{{f_2}}} - \dfrac{d}{{{f_1}{f_2}}}$
Were, ${f_1}$ is the focal length of convex lens $ = 1{\text{ m}}$
${f_2}$ is the focal length of concave lens $ = 0.25{\text{ m}}$
$d$ is the distance between the lenses $ = 0.75{\text{ m}}$
$\dfrac{1}{f} = \dfrac{1}{{ + 1}} + \dfrac{1}{{ - 0.25}} - \dfrac{{0.75}}{{1 \times \left( { - 0.25} \right)}}$
$ \Rightarrow \dfrac{1}{f} = 1 - 4 + 3$
Further simplifying we get,
$ \Rightarrow \dfrac{1}{f} = 4 - 4$
$ \therefore \dfrac{1}{f} = 0$
Therefore, the focal length will be infinity and the power will become zero. As the power is zero therefore if the incident beam of light is parallel then the emerging beam of light will be also parallel.
Therefore, the correct answer is option A.
Additional information:
Power of a lens: The power of a lens is defined as the reciprocal of its focal length. It is represented by the letter $P$. The power $P$ of a lens of focal length $f$ is given by,
$P = \dfrac{1}{f}$
The SI unit of power is diopter when focal length is in meters. It is noted by $D$. Hence one diopter is a power of lens whose focal length is 1 metre.
Note: A Convex lens is one which is thinner at the sides and thick at centre. A concave lens is one which is thicker at the sides and thin at the centre. When two or more lenses are combined then the power of the combined lens is the sum of individual power of lenses.
Complete step by step answer:
From the question, convex lenses and concave lenses are $0.75{\text{ m}}$ apart.
Therefore, from the power of combination of lenses.
$\dfrac{1}{f} = \dfrac{1}{{{f_1}}} + \dfrac{1}{{{f_2}}} - \dfrac{d}{{{f_1}{f_2}}}$
Were, ${f_1}$ is the focal length of convex lens $ = 1{\text{ m}}$
${f_2}$ is the focal length of concave lens $ = 0.25{\text{ m}}$
$d$ is the distance between the lenses $ = 0.75{\text{ m}}$
$\dfrac{1}{f} = \dfrac{1}{{ + 1}} + \dfrac{1}{{ - 0.25}} - \dfrac{{0.75}}{{1 \times \left( { - 0.25} \right)}}$
$ \Rightarrow \dfrac{1}{f} = 1 - 4 + 3$
Further simplifying we get,
$ \Rightarrow \dfrac{1}{f} = 4 - 4$
$ \therefore \dfrac{1}{f} = 0$
Therefore, the focal length will be infinity and the power will become zero. As the power is zero therefore if the incident beam of light is parallel then the emerging beam of light will be also parallel.
Therefore, the correct answer is option A.
Additional information:
Power of a lens: The power of a lens is defined as the reciprocal of its focal length. It is represented by the letter $P$. The power $P$ of a lens of focal length $f$ is given by,
$P = \dfrac{1}{f}$
The SI unit of power is diopter when focal length is in meters. It is noted by $D$. Hence one diopter is a power of lens whose focal length is 1 metre.
Note: A Convex lens is one which is thinner at the sides and thick at centre. A concave lens is one which is thicker at the sides and thin at the centre. When two or more lenses are combined then the power of the combined lens is the sum of individual power of lenses.
Recently Updated Pages
Write the IUPAC name of the given compound class 11 chemistry CBSE
Write the IUPAC name of the given compound class 11 chemistry CBSE
Write the IUPAC name of the given compound class 11 chemistry CBSE
Write the IUPAC name of the given compound class 11 chemistry CBSE
Write the IUPAC name of the given compound class 11 chemistry CBSE
Write the IUPAC name of the given compound class 11 chemistry CBSE
Trending doubts
Fill the blanks with the suitable prepositions 1 The class 9 english CBSE
Which are the Top 10 Largest Countries of the World?
How do you graph the function fx 4x class 9 maths CBSE
Distinguish between the following Ferrous and nonferrous class 9 social science CBSE
The term ISWM refers to A Integrated Solid Waste Machine class 10 social science CBSE
The Equation xxx + 2 is Satisfied when x is Equal to Class 10 Maths
Difference between Prokaryotic cell and Eukaryotic class 11 biology CBSE
Which is the longest day and shortest night in the class 11 sst CBSE
In a democracy the final decisionmaking power rests class 11 social science CBSE