**Answer:**

<h2>6.67 m/s²</h2>

**Explanation:**

The acceleration of an object given it's mass and the force acting on it can be found by using the formula

f is the force

m is the mass

From the question we have

We have the final answer as

<h3>6.67 m/s²</h3>

Hope this helps you

**Answer:**

(a) Q = 142.67 W

(b) Basal Metabolic Rate = 178.33 W

**Explanation:**

**(a) **

We can find the heat radiated by the person by using Stefan-Boltzman's law:

where,

Q = heat radiated per second = ?

σ = Stefan-Boltzman Constant = 5.6703 x 10⁻⁸ W/m².k⁴

A = Surface Area = 2 m²

T = Temperature of Skin = 30° C + 273 = 303 k

Ts = Temperature of room = 18° C +273 = 291 k

Therefore,

<u></u>

<u>**Q = 142.67 W**</u>

<u></u>

**(b)**

Since the heat calculated in part (a) is 80 percent of basal metabolic rate. Therefore,

<u>**Basal Metabolic Rate = 178.33 W**</u>

**Answer:**

The angle of incidence is greater than the angle of refraction

**Explanation:**

Refraction occurs when a light wave passes through the boundary between two mediums.

When a ray of light is refracted, it changes speed and direction, according to Snell's Law:

where
:

is the index of refraction of the 1st medium

is the index of refraction of the 2nd medium

is the angle of incidence (the angle between the incident ray and the normal to the boundary)

is the angle of refraction (the angle between the refracted ray and the normal to the boundary)

In this problem, we have a ray of light passing from air into clear plastic. We have:

(index of refraction of air)

approx. (index of refraction in clear plastic)

Snell's Law can be rewritten as

And since , we have

And so

Which means that

**The angle of incidence is greater than the angle of refraction**

**Answer:**

the string and metre rule

**Explanation:**

**Answer:**

Option A

**Explanation:**

Angular resolution for any optical equipment can be defined as the ability of that tool to differentiate the smallest details of the image formed.

The angular resolution is given by:

(1)

where

= Angular Resolution

= wavelength

d = diameter of the lens

Now,

As per the question:

If the diameter of the lens is doubled, i.e., d' = 2d

Then

From eqn (1):

Thus when the diameter is doubled the angular resolution becomes half of its original value.