Which type of mouthparts is present on the lateral side of the pre-oral cavity in cockroach?

Isogamous condition with non-flagellated gametes is found in:

The atomic numbers of elements $A$,$B$,$C$ and $D$ are $Z-1$,$Z$,$Z+1$ and $Z+2$,respectively. If $B$ is a noble gas,choose the correct statements from the following:
$(1)$ $A$ has high electron affinity
$(2)$ $C$ exists in $+2$ oxidation state
$(3)$ $D$ is an alkaline earth metal

The voltage gain of a transistor in common emitter configuration is $160$. The resistances in base and collector sides of the circuit are $1 \text{ k}\Omega$ and $4 \text{ k}\Omega$ respectively. If the change in base current is $100 \mu A$, then the change in output current is:

One root of the equation $\cos x - x + \frac{1}{2} = 0$ lies in the interval

Calculate the volume strength of $1.5 \ N \ H_2O_2$.