Question

The speed of light in vaccum is 3 × 10^8 m/s. Sunlight takes about 8 minutes to reach the earth. Express distance of Sun from Earth in standard form.

Answer 1

Answer:

Speed of light in vacuum = 3 x 10⁸ m/s

Time taken by sunlight to reach Earth = 8 minutes.

1 minute = 60 seconds

∴ 8 mins = 8 x 60 = 480 seconds

We know that,

$Speed=\dfrac{Distance}{Time}$

So,

Distance = Speed x Time

Substituting the values,

=$Distance=3\times10^8\times480$

=$Distance=1440\times10^8$

[We can take 3 zeros out from 1440]

=$Distance=1.44\times10^8\times10^3$

[ As per the law of exponents, $x^a\timesx^b=x^a^b$]

=$Distance=1.44\times10^1^1$

∴ The distance between the Earth and the Sun in standard form is 1.44 x 10¹¹.

Knowledge Bytes:

→ Standard Form

Standard form, scientifically known as Scientific notation is the writing down of numbers that are too large and inconvenient to be expressed as the number itself in the form of exponents is known as writing down in standard form.

Usually, we write down the scientific notation with the base as 10.

→ Law of exponent - a¹ x a² = a³

When two numbers in exponential form are multiplied and the two numbers have the same base, we just need to add the exponents and the base remains the same.