Physics

The molecules of a given mass of a gas have root mean square speeds of 100ms^-1 at 27 C° and 1.00 atmospheric pressure. What will be the root mean square speeds of the molecules of the gas at 127°C and 2.0 atmospheric pressure?

Temperature dependence of resistivity ρ(T) of semiconductors, insulators and metals is significantly based on the following factors:
(a) Number of charge carriers can change with temperature T.
(b) Time interval between two successive collisions can depend on T.
(c) Length of material can be a function of T.
(d) Mass of carriers is a function of T.

Consider a simple circuit shown in figure stands for a variable resistance R'. R' can vary from R₀to infinity, r is internal resistance of the battery (r <(a) Potential drop across AB is nearly constant as R' is varied.
(b) Current through R' is nearly a constant as R' is varied.
(c) Current I depends sensitively on R'
(d) I ≥ V/r + R always;

Kirchhoff's junction rule is a reflection of
(a) Conservation of current density vector.
(b) Conservation of charge.
(c) The fact that the momentum with which a charged particle approaches a junction is unchanged (as a vector) as the charged particle leaves the junction.
(d) The fact that there is no accumulation of charges at a junction.

The volume of a given mass of a gas at 27°C, 1 atm is 100 cc. What will be its volume at 327°C?

Which of the following characteristics of electrons determines the current in a conductor?
(a) Drift velocity alone
(b) Thermal velocity alone
(c) Both drift velocity and thermal velocity
(d) Neither drift nor thermal velocity

The volume of a given mass of a gas at 27°C, 1 atm is 100 cc. What will be its volume at 327°C?

A metal rod of length 10 cm and a rectangular cross-section of 1 cm x 1/2 cm is connected to a battery across opposite faces. The resistance will be
(a) Maximum when the battery is connected across 1 cm x 1/2 cm faces
(b) Maximum when the battery is connected across 10 cm x 1 cm faces
(c) Maximum when the battery is connected across 10 cm x 1/2 cm faces
(d) Same irrespective of the three faces

Calculate the number of atoms in 39.4 g gold. Molar mass of gold is 197g mole^-1.

Two cells of emfs approximately 5 V and 10 V are to be accurately compared using a potentiometer of length 400 cm.4. 
(a) The battery that runs the potentiometer should have voltage of 8 V.
(b) The battery of potentiometer can have a voltage of 15 V and R adjusted so that the potential drop across the wire slightly exceeds 10 V.

(c) The first portion of 50 cm of wire itself should have a potential drop of 10 V.
(d) Potentiometer is usually used for comparing resistances and not voltages.