NEET Practice Questions (MCQs) with Answers & Solutions

The value of the gravitational constant (G) in the MKS system is $6.67 imes 10^{-11} ext{Nm}^2/ ext{kg}^2$. To convert this to CGS units, we need to convert meters to centimeters and kilograms to grams. 1 meter = 100 cm and 1 kilogram = 1000 grams. Therefore, $G$ in CGS units is $6.67 imes 10^{-11} imes (100^3)/(1000^2) = 6.67 imes 10^{-8} ext{dyn-cm}^2/ ext{gm}^2$. Hence, the correct option is $6.67 imes 10^{-8}$.

1 MeV (Mega electron Volt) is equal to $10^6$ electron Volts. Therefore, 1 MeV = $10^6$ eV.

Length, time and velocity cannot enter in to the list of fundamental quantities because velocity can be expressed in terms of length and time.

1 radian is equal to the angle subtended at the center of a circle by an arc whose length is equal to the radius of the circle. To convert radians to degrees, we use the formula: $1 ext{ rad} = rac{180}{ ext{Ï€}} ^ ext{circ}$.

$ 1 amu = 1.66 \times 10 ^ {-27 } kg $ $ = 1.66 \times 10 ^ {-24} gm $ $ 1 gm = 6.023 \times 10 ^ {23} amu $

Power is defined as the rate at which work is done or energy is transferred. The units of power are watt (W), which is equivalent to joule/second (J/s). Other valid units of power include $( ext{ampere})^2 imes ext{ohm}$ and $ ext{ampere} imes ext{volt}$. However, ampere/volt does not represent a unit of power.

Angular acceleration in the SI system is measured in radians per second squared ($ ext{rad}/( ext{sec})^2$). This unit expresses how quickly the angular velocity of an object is changing with time.

The universal gravitational constant (G) is defined in Newton's law of gravitation, which states that the force (F) between two masses (m1 and m2) is proportional to the product of their masses and inversely proportional to the square of the distance (r) between them. Mathematically, it is given by: $$ F = G rac{m1 imes m2}{r^2} $$. Rearranging this equation to solve for G, we get: $$ G = rac{F imes r^2}{m1 imes m2} $$. The unit of force (F) is Newton (N), the unit of distance (r) is meter (m), and the unit of mass (m) is kilogram (kg). Therefore, the unit of G is: $$ [G] = rac{N imes m^2}{kg^2} $$, which simplifies to $$ N m^2 kg^{-2} $$.