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A metal is illumimated by light of two d...

A metal is illumimated by light of two different wavelength `248nm` and `310 nm` . The maximum speeds of the photoelectrons corresponding in these wavelength are `u_(1) and u_(2)` respectively . If the ratio `u_(1) : u_(2) = 2 : 1` and `hc = 1240 eVnm `, the work function of the meal is nearly

A

3.7 eV

B

3.2 eV

C

2.8 eV

D

2.5 eV

Text Solution

Verified by Experts

The correct Answer is:
A
`K_("max")=(hc)/lambda -phi_(0)`
`(K_(max_(1)))/(K_(max_(2)))=4/1 =((1240)/248-phi_(0))/((1240)/310-phi_(0))`
`rArr phi_(0) = 3.7 eV `
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