Consider a circular disc of radius 20 cm with centre located at the origin. A circular hole of radius 5 cm is cut from this disc in such a way that the edge of the hole touches the edge of the disc. The distance of centre of mass of residual or remaining disc from the origin will be

Refer to the circuit diagram given in the figure. which of the following observations are correct?

A. Total resistance of circuit is $6 \Omega$

B. Current in Ammeter is 1 A

C. Potential across $A B$ is 4 Volts.

D. Potential across CD is 4 Volts

E. Total resistance of the circuit is $8 \Omega$.

Choose the correct answer from the options given below:

The electric field of an electromagnetic wave in free space is $\overrightarrow{\mathrm{E}}=57 \cos \left[7.5 \times 10^6 \mathrm{t}-5 \times 10^{-3}(3 x+4 y)\right](4 \hat{i}-3 \hat{j}) N / C$. The associated magnetic field in Tesla is

The electric flux is $\phi=\alpha \sigma+\beta \lambda$ where $\lambda$ and $\sigma$ are linear and surface charge density, respectively. $\left(\frac{\alpha}{\beta}\right)$ represents