Which of the following is monoatomic?

The magnetic flux near the axis and inside the air-core solenoid of length $60 \ cm$ carrying current $I$ is $1.57 \times 10^{-6} \ Wb$. Its magnetic moment will be (cross-sectional area of a solenoid is very small as compared to its length,$\mu_0 = 4\pi \times 10^{-7} \ SI \ units$). (in $A \ m^2$)

Which one of the following population interactions is widely used in medical science for the production of antibiotics?

Which of the following organelles contains hydrolytic enzymes?

Which of the following is $NOT$ a characteristic of chemisorption?

The angle between the lines whose intercepts on the axes are $a, -b$ and $b, -a$ respectively is .....