Which of the following statements is/are true?a)A convex lens has 4 di...
Positive sign with power and focal length indicates that the given lens is convex.
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Which of the following statements is/are true?a)A convex lens has 4 di...
Convex mirror as well as lens has positive focal length and positive power
Here, F=0.25
P=1/F
P=1/0.25
P=+4
Which of the following statements is/are true?a)A convex lens has 4 di...
Statement a) A convex lens has 4 dioptre power having a focal length of 0.25 m.
Explanation:
To understand this statement, we need to first understand what dioptre power and focal length mean in the context of lenses.
1. Dioptre Power:
Dioptre power is a unit of measurement used to quantify the optical power of a lens. It is denoted by "D" and is equal to the reciprocal of the focal length of the lens in meters. Mathematically, it can be represented as:
Dioptre Power (D) = 1 / Focal Length (m)
2. Focal Length:
The focal length of a lens is the distance between the lens and the point where parallel rays of light converge or appear to diverge from. It is denoted by "f" and is measured in meters.
Now, let's analyze the statement:
a) A convex lens has 4 dioptre power having a focal length of 0.25 m.
According to the formula mentioned above, the dioptre power of a lens is equal to the reciprocal of its focal length. Therefore, if the focal length is 0.25 m, the dioptre power can be calculated as:
Dioptre Power (D) = 1 / Focal Length (m)
Dioptre Power (D) = 1 / 0.25
Dioptre Power (D) = 4 D
So, the dioptre power of a lens with a focal length of 0.25 m is indeed 4 dioptres. Hence, statement a) is true.
To summarize:
- A convex lens with a focal length of 0.25 m has a dioptre power of 4 D.
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