Tag: physics

the closed loop gain is given by $A _{cl}=\dfrac{A}{1+A \beta}$. since the open loop gain is large, the closed loop gain almost remains a constant, as it will be independent of open loop gain 

Input current in an ideal operational amplifier   $i = \dfrac{V}{Z}$
Since,  input impedance of the ideal operational amplifier is infinite  $i.e. Z = \infty$
$\implies \ i =\dfrac{V}{\infty}= 0$

Since, we know that SI unit of energy is represented by Joule. Hence, let us convert all the different units in the form of Joules.

Astronomers estimate the distance of nearby objects in space by using a method called stellar parallax, or trigonometric parallax. Simply put, they measure a star's apparent movement against the background of more distant stars as Earth revolves around the sun

Given,

$\theta =0.03316\,\,rad$

Also $b = \mathrm { AB } =$ diameter of earth $= 1.276 \times 10 ^ { 7 } \mathrm { m }$

Now d $=\dfrac{b}{\theta }=\dfrac{1.276\times {{10}^{7}}}{0.03316\,}=3.84\times {{10}^{8}}\text{m}$

Hence, distance between earth and moon is $3.84\times {{10}^{8}}\text{m}$

Spherometer is an instrument which is used to measure the curvature of spherical surfaces.

Parallax method is used for the measurement of planet distance and also used to measure distance of starts and planets

Optical microscopes are enabled with objective fitted with lenses with different magnifications. This helps to magnify a small objects and so necessary measurements.

In parallax method, an approximation is made that distance between a point on the earth and the planet is very large as compared to the distance between two points on the earth's surface.

$Answer:-$ D