The thermo emf of a thermocouple is given by $E = aT + bT^2$,where $\frac{a}{b} = -200^{\circ}C$. If the cold junction is kept at $30^{\circ}C$,then the inversion temperature is ($\varepsilon$ in volt,$T$ in centigrade). (in $K$)

Le Chatelier's principle is not applicable to

Black Jack is an ore of

If $x^2+2px-2p+8>0$ for all real values of $x$,then the set of all possible values of $p$ is

When substance $A$ reacts with water,it produces a combustible gas $B$ and a solution of substance $C$ in water. When another substance $D$ reacts with solution $C$,it produces the same gas $B$ even when reacting with dilute sulfuric acid at room temperature. $A$ imparts a golden yellow color to the non-luminous flame of a Bunsen burner. What are $A$,$B$,$C$,and $D$ respectively?

Initially a photon of wavelength $\lambda_1$ falls on a photocathode and emits an electron of maximum energy $E_1$. If the wavelength of the incident photon is changed to $\lambda_2$,the maximum energy of the electron emitted becomes $E_2$. Then the value of $hc$ ($h=$ Planck's constant,$c=$ velocity of light) is