Which of the following groups of transition metals are known as coinage metals?

Order of toxicity among ammonia,urea and uric acid (from lower to higher) is

Which one of the following sets correctly represents the increase in the paramagnetic property of the ions?

$A$ diverging lens with a focal length of magnitude $25 \, cm$ is placed at a distance of $15 \, cm$ from a converging lens with a focal length of magnitude $20 \, cm$. $A$ beam of parallel light falls on the diverging lens. The final image formed is:

Why does copper not replace hydrogen from acids?

$A$ clock pendulum made of invar has a period of $0.5 \, s$ at $20^{\circ} C$. If the clock is used in a climate where the temperature averages to $30^{\circ} C$, how much time does the clock lose in each oscillation? (For invar, $\alpha = 9 \times 10^{-7} /{ }^{\circ} C$, $g = \text{constant}$)