Physics Questions

Magma is injected into surrounding rock forming an igneous intrusive.

Actually it is a plutonic formation in which magma present beneath Earth surface deforms the shape of rocks present above it
 

The size of gear is usually specified by pitch circle diameter.

without this centripetal force, circular motion is not possible. It acts radially towards the centre and if this force is removed there will be no circular motion but the revolving body will fly off at a tangent.

Echolocation is an adaptation bats use to hunt insects in flight, locate flowering plants and find warm places for hibernation.

Black  surfaces are good emitters of heat ( They are also good absorbers of heat). If the black surface is rough too, the emitting will be better. So (b) is the correct answer. Shining surfaces reflect back radiation. So if the black surface is also shining the effectiveness of emitting heat is lessened.

When a running car stops suddenly, the passengers tends to lean forward because of Inertia of motion.

p type of semiconductor is obtained when Silicon is doped with a trivalent impurity like Aluminium. Aluminium is a p-type dopant, which means that when a semiconductor i.e. silicon is doped with aluminium, it creates a hole (positively charged carrier) by accepting an electron from the silicon atom. Electrical conductivity of semiconductors increasesand resistivity remains the same

General purpose gloves - utility gloves are recommended for cleaning procedures, such as handling soiled linens or decontaminating care areas. Utility gloves are more tear and puncture resistant than other gloves.