Which of the following statements is correct for diamagnetic materials?

The surface of a metal is illuminated with light of wavelength $400 \, nm$. The kinetic energy of the ejected photoelectrons is found to be $1.68 \, eV$. The work function of the metal is .................. $eV$ $(hc = 1240 \, eV-nm)$.

$A$ bimetallic strip is formed out of two identical strips,one of copper and the other of brass. The coefficients of linear expansion of the two metals are $\alpha_C$ and $\alpha_B$. On heating,the temperature of the strip increases by $\Delta T$ and the strip bends to form an arc of radius $R$. Then $R$ is proportional to

In algae with a haplontic life cycle,which of the following processes involves mitosis?

Two planoconvex lenses each of focal length $10 \, cm$ and refractive index $3/2$ are placed as shown. In the space left, water $(R.I = 4/3)$ is filled. The whole arrangement is in air. The optical power of the system is (in diopters):

The angle between the lines whose direction cosines satisfy the equations $l+m+n=0$ and $l^2+m^2-n^2=0$ is