## What happens to the focal length of a mirror when it is immersed in water?

In case of spherical mirrors (both concave and convex), there will be **no change** in the focal length of the mirrors when immersed in water. This is because the focal length of mirrors does not depend on the external medium in which it is held.

## What happens when a mirror is dipped in water?

When the mirror is dipped in water, **a mirror reflects light using its polished surface**. It does not depend on the medium to define its properties, unlike the lens.

## What is the change in focal length when concave lens is immersed in water?

Answer : If a concave mirror is immersed in a liquid of refractive index n, focal length f of the mirror **does not change**.

## What is the formula for focal length of a mirror?

However, as discussed above, in the small-angle approximation, the focal length of a spherical mirror is one-half the radius of curvature of the mirror, or **f=R/2**.

## Will focal length change in water?

**Yes.** **Focal length changes when lens is immersed in water**.

## What is effect on the focal length of the convex mirror when it is immersed in a liquid of greater refractive index *?

**if n decreases, f increases**. So if you immerse the convex lens in a liquid whose refractive index is greater than refractive index of material of lens then it will change its nature and become concave lens and thus it will start diverging the rays rather than focusing them on a single point.

## Does focal length change in water?

**Yes.** **Focal length changes when lens is immersed in water**.

## When a concave lens of refractive index 1.5 is immersed in water it will become?

In the given case, concave lens is immersed in a medium having refractive index greater than the refractive index of the material of the lens (1.65 > 1.5). Therefore, it will behave as a **converging lens**.

## Is immersed in water μ 4 3 The focal length of the mirror in water will be?

Focal length of the mirror **remains unchanged**.

## How do you find focal length?

The typical focal length formula looks as follows: **1/Focal length = 1/Image distance + 1/Object distance** , where: Image distance and Object distance are given in mm.

## What is focal length class 10th?

**The distance between the convex lens or a concave mirror and the focal point of a lens or mirror** is called the focal length. It is the point where parallel rays of light meet or converge.

## What is the focal length of the lens if it is immersed in water?

Now since the focal length is inversely proportional to the (μ−1), therefore **the focal length will increase**. Hence the focal length of the lens increases when it is immersed in the water.

## How does focal length change with refractive index?

Since from lens makers formula we can observe that focal length of lens is inversely proportional to refractive index of medium of lens . Hence net refractive index of lens decreases when it is dipped in a denser medium than air, hence **focal length increases**.

## When the whole lens is immersed in a liquid of refractive index 1.6 The nature of the lens will be?

As the relative refractive index is less than 1, therefore the lens will behave like a **convex lens**.

## What will be focal length of lens if it is immersed in a liquid of greater refractive index than lens?

Thus, **the focal length of the lens will increase**. When any lens or glass slab is immersed in a liquid whose refractive index is equal to that of lens, refractive index of lens will be equal to 1 relative to that liquid. The focal length of the lens in this case, will tend to infinity. ⇒f=∞ .

## What happens when a convex lens of refractive index 1.5 is immersed?

एक उत्तल लेंस को जिसके पदार्थ का अपवर्तनांक 1.5 है। को (i)1.6 , (ii) 1.3 , (iii) 1.5 **अपवर्तनांक वाले द्रव में डुबाया जाता है**। प्रत्येक स्थिति में लेंस की फोकस ज्ञात कीजिए । वायु में लेंस की फोकस दूरी 5 सेमी ।

## When a convex mirror of focal length f produces an image 1 th’n of the size of the object then distance of the object from the mirror is?

**u=(n+1)f**.

## When a concave mirror of focal length f is immersed in water its focal length becomes f then?

explanation : We know, law of reflection doesn't depend on refractive index of medium. so, when A concave mirror of focal length f (in air ) is immersed in water then, **the focal length of the mirror in water remains constant** e.g., f.

## How do you find the focal length when refractive index is given?

Step 1: Identify the index of refraction, n , outer radius R1 , and inner radius R2 . Step 2: Substitute the values from step 1 into the lensmaker equation, **1f=(n−1)(1R1−1R2) 1 f = ( n − 1 ) ( 1 R 1 − 1 R 2 ) .** **Step 3: Solve for the focal length, f** .

## What is focal length class 7?

**The distance between the convex lens or a concave mirror and the focal point of a lens or mirror** is called the focal length. It is the point where parallel rays of light meet or converge.

## How is focal length related to refractive index?

Since from lens makers formula we can observe that focal length of lens is **inversely proportional** to refractive index of medium of lens . Hence net refractive index of lens decreases when it is dipped in a denser medium than air, hence focal length increases.

## How do you find the focal length from the refractive index?

Step 1: Identify the index of refraction, n , outer radius R1 , and inner radius R2 . Step 2: Substitute the values from step 1 into the lensmaker equation, 1f=(n−1)(1R1−1R2) 1 f = ( n − 1 ) ( 1 R 1 − 1 R 2 ) . Step 3: Solve for the focal length, f .

## How do you find the focal length of a refractive index?

Use a spherometer to measure the radius of curvature of the two lens faces r1 and r2. Use any standard method to measure the focal length of the lens f. Use the lens makers formula **1f=(n−1)(1r1+1r2)** to find the refractive index n of the lens.

## When the whole lens is immersed in a liquid of refractive index 1.6 The nature of the lens will be a converging B diverging c same as glass Pate D None?

Solution : Refractive index of the surrounding medium water is less than that of refractive index of glass and hence **nature of the lens will remain converging**. Hence, option (c) is correct.

## When a concave lens of refractive index 1.5 is immersed in water it will be come?

In the given case, concave lens is immersed in a medium having refractive index greater than the refractive index of the material of the lens (1.65 > 1.5). Therefore, it will behave as a **converging lens**.

## At what distance from a convex lens of focal length 30 cm and object should be placed so that the size of image be half of object?

The object should be placed **15 cm** in front of the mirror.

## Under which of the following conditions will a convex mirror of focal length f produce an image?

so, we conclude that, A convex mirror always forms **erect, virtual and diminished image**. hence, Under which of the following conditions will a convex mirror of focal length f produce an image that is erect, diminished and virtual (d) always.

## What is the formula of focal length of lens?

The focal length is half the radius of curvature and is as **f=R2** f = R 2 , where f is the focal length, and R is the radius of curvature.

## What is focal length class 10 Ncert?

Focal length: The focal length (denoted by FP in the fig.) is **the distance between the pole P and the principal focus F of a curved mirror**. The focal length is half the radius of curvature. Focal length = Radius of curvature/2 .

## Does the focal length of a lens change in water?

**Yes.** **Focal length changes when lens is immersed in water**.