The kineticenergies of photoelectrons emitted from the metal are K₁ & K₂ when it is irradiated with lights of wavelenghts ₁ & ₂ The workfunction of the matal is

K_{1 1} - K_{2 2}/₁-₂

K_{1 1} + K_{2 2}/₁ +₂

K_{1 2} - K_{2 1}/₂-₁

K_{1 2}  + K₂ 1/₂ +₁

ans is a

In young's double slit interference experiment the incident light consists of 2 wavelenghts ₁ & ₂  & the slit separation d & D is the distance between the slits & the screen.The maxima due to the two wavelenghts will coincide at a dist from the central maximum which is

₁+₂/2(D/d)

₁ -₂/2(D/d)

Least common multiple of ₁ D/d and ₂D/d

Highest common multiple of ₁ D/d and ₂D/d

ans is c

A beaker contains water =4/3 filled to a ht of 32 cms.A concave mirror is fixed 6 cm above the surface of water. An object is placed at the bottom of the beaker & its image is formed14 cms below the surface of water. The focal lenght of the mirror

8

12

16

20

ans is 12cm

U r given several identical resistances each of value 10ohms & each capable of carryin a max current of 1 A.It is requied to make a suitable combination of these resistances to produce a resistance of 5 ohm which cancarry current of 4 A.Themin no of resistances required is

4

10

8

20

ans is 8

A carbon & an aluminium wire are connected in series .If the combination has resistance of 30 ohms at 0⁰C,what is the resistance of each wire at 0⁰C so that resistance of the combination does not change with temperature. 

_c=-0.5x10^-3/⁰C _Al=4 x10^-3/⁰C

10 80

80/3 10/3

40/3 80/3

40 80

ans is 80/3 10/3

If a,b are positive quantities and a₁=a+b/2,b₁=under root a₁b*a₂=a₁+b_1//2,b₂=under root a₂b₁ & so on lim n tends to infinity is equal to ?

ans is under root  b²-a² /cos ^-1 a/b   (q taken from tatamac graw hill comp aieee 2008-pg 26.26)

A hemisphere of radius R is charged uniformly with surface density of charge sigma.What will be the potential at the centre?

sigmaR/2E₀

sigma/4E_o

sigma/2E₀

4sigmaR/3E₀

( E_o  is permittivity )

The sum of th infinte series cot^-12+cot^-18+cot^-118+cot^-132....is equal to

pie/4

pie/2

3pie/4

none

ans is pie/4

A parellel combination of 0.1Mohms resistor & a 10micro farads capacitor is connected across a 1.5V source of negligible resistance.The time (in seconds) required for the capacitor to get charged up to 0.75V is appoxmately

infinty

log_e2

log₁₀2

0

ans is 0

the normal to the curve x=a(cos@+@sin@), y=a(sin@-@cos@), at any point @ is such that:

it makes an angle pie/2+@ with the x axis

it passes through th origin

it is at constant dist from th origin

ans is c

ans given is 2 but celestine allamraju are u'll sure its 0 QUESTION TAKEN FROM TMH'S MATHEMATICS FOR AIEEE.

The no of +ve integral pairs(a,b) satisfying d eq tan^-1a+tan^-1b=tan^-17 is

0

2

4

infinte

ans is 2

/2cosec^2(1/2tan^-1/) +/2sec^2(1/2tan^-1/)=

(alpha+beta)(alpha square+beta square)

(alpha-beta)(alpha square+beta square)

(alpha-beta)(alpha square-beta square)

(alpha+beta)(alpha square-beta square)

ans is

(alpha+beta)(alpha square+beta square)

tan^-1(xcos/1-xsin)-cot^-1(cos/x-sin) =

pie/2-

/2

pie/4-/2

ans is

The max. n min value of f(x)=absinx+b(1-a^2)^1/2cosx+c lie in the interval(assumin IaI less than 1 n b greater than 0)

a.[b-c,b+c]

b.[a-c,a+c]

c.[c-b,b+c]

d.none

ans is c