Home
Class 12
PHYSICS
Electrons are emitted by a hot filament ...

Electrons are emitted by a hot filament and are accelerated by an electric field as shown in figure .The two stops at the left ensure that the electron beam has a uniform cross-section.

A

(a)The speed of the electron is more at B than at A.

B

(b)The electric current is from left to right.

C

(c )The magnitude of the current is larger at B than at A .

D

(d)The current density is more at B than at A.

Text Solution

Verified by Experts

The correct Answer is:
A
Promotional Banner

Topper's Solved these Questions

  • ELECTRIC CURRENT IN CONDUCTORS

    HC VERMA|Exercise Exercises|84 Videos

  • ELECTRIC CURRENT IN CONDUCTORS

    HC VERMA|Exercise Objective 1|16 Videos

  • DISPERSION AND SPECTRA

    HC VERMA|Exercise Exercises|11 Videos

  • ELECTRIC CURRENT THROUGH GASES

    HC VERMA|Exercise Exercises|23 Videos

Similar Questions

Explore conceptually related problems

An electron of mass m and charge e initially at rest gets accelerated by a constant electric field E . The rate of change of de-Broglie wavelength of this electron at time t ignoring relativistic effects is

An irregular rod of same uniform material as shown in figure is conducting heat at a steady rate. The temperature gradient at various sections versus area of cross section graph will be

Solve the follwing example . An electron enters a magnetic field at right angles to , it as shown in figure 13.36 The direction of force acting on the electrons will be …….

Two infinitely large charged planes having uniform suface charge density +sigma and -sigma are placed along x-y plane and yz plane respectively as shown in the figure. Then the nature of electric lines of forces in x-z plane is given by:

An electron is projected as in figure with kinetic energy K, at an angle theta=45^(@) between two charged plates. The magnitude of the electric field so that the electron just fails to strike the upper plate, should be greater than:

A wall consists of alternating blocks of length 'd' and coefficient of thermal conductivity k_(1) and k_(2) respectively as shown in figure. The cross sectional area of the blocks are the same. The equivalent coefficient of thermal conductivity of the wall between left and right is . . . . .

Monichromatic light of wavelength 632.8 nm Is produced by a helium-neon laser.The power emitted is 9.42 mW. (b)How many photons per second,on the average ,arrive at a target irradiated by this beam ? (Assume the beam to have uniform cross-section which is less than the target area),and (c )How fast does a hydrogen atom have to travel in order to have the same moementum as that of the photon?

A copper rod (initially at room temperature 20^(@)C ) of non-uniform cross section is placed between a steam chamber at 100^(@)C and ice-water chamber at 0^(@)C . A and B are cross sections are as shown in figure. Then match the statements in column -I with results in columns-II using comparing only between cross section A and B . (The mathematical expressions in column-I have usual meaning in heat transfer). {:(,"Column-I",,"Column-II"),((A),"initially rate of heat flow" ((dQ)/(dt))"will be ",(p),"Maximum at section" A),((B),"At steady state rate of heat flow" ((dQ)/(dt)) "will be ",(q),"Maximum at section" B),((C),"At steady state temperature gradient" |((dT)/(dx))| "will be " ,(r),"Minimum at section B"), ((D), "At steady state rate of change of temperature"((dT)/(dt)) " at a certain point will be",(s),"Same for all section"):}

An electron and a proton are in a uniform electric field the ratio of their acceleration will be ..........

An electron falls freely in electric field of 9.1 xx 10^3 NC^(-1) , then acceleration of electron is .......