A body of mass 10 mg is moving with a velocity of 100 ms-1. The wavelength of de-Broglie wave associated with it would be (Note: h = 6.63 × 10^(-34) Js)

The correct option is 6.63 × 10^-31 m.

To find the de-Broglie wavelength associated with the moving body, we use de-Broglie's wavelength formula:
$$\lambda =\frac{h}{p}=\frac{h}{m\cdot v}$$
where:
• $\lambda$ is the de-Broglie wavelength,
• $h$ is Planck's constant, given as 6.63 × 10^-34 J s,
• $m$ is the mass of the body, and
• $v$ is the velocity of the body.

First, we must convert all given quantities into Standard International (SI) units:
• Mass of the body, $m=10\text{mg}=10\times {10}^{-6}\text{kg}={10}^{-5}\text{kg}$
• Velocity of the body, $v=100{\text{ms}}^{-1}={10}^2{\text{ms}}^{-1}$

Now, we calculate the momentum ($p$) of the body:
$$p=m\cdot v={10}^{-5}\text{kg}\times {10}^2{\text{ms}}^{-1}={10}^{-3}{\text{kg ms}}^{-1}$$

Next, substitute the values of $h$ and $p$ into the de-Broglie wavelength equation:
$$\lambda =\frac{6.63\times {10}^{-34}}{{10}^{-3}}$$
$$\lambda =6.63\times {10}^{-34-(-3)}$$
$$\lambda =6.63\times {10}^{-31}\text{m}$$

Therefore, the de-Broglie wavelength associated with the body is 6.63 × 10^-31 m.