Answer:
b) vary with the frequency of the light
Explanation:
The phone electric effect can be expressed as
K.E=(hv -W•)
Where K.E is the Kinectic energy
W• = work function of the metal
ν =frequency of the radiation
h = Planck's constat
Then, we can see that K.E is proportional linearly to "v" in the equation above.
Therefore, When light is directed on a metal surface, the kinetic energies of the photoelectrons vary with the frequency of the light
Answer:
a)KE=878.8 J
b)W=2636.4 J
Explanation:
Given that
mass ,m = 65 kg
Initial speed ,u = 5.2 m/s
a)
We know that kinetic energy KE is given as follows

m=mass
u=velocity
Now by putting the values in the above equation we get

KE=878.8 J
b)
We know that
Work done by all forces = Change in the kinetic energy
The final velocity , v= 2 u = 2 x 5.2 m/s
v= 10.4 m/s

Now by putting the values in the above equation we get

W=2636.4 J
a)KE=878.8 J
b)W=2636.4 J
Answer:
The correct answer is "22.27 hours".
Explanation:
Given that:
Radioactive isotope activity,
= 490,000 Bq
Activity,
= 110,000 Bq
Time,
= 48 hours
As we know,
⇒ 
or,
⇒ 
By taking "ln", we get
⇒ 
By substituting the values, we get
⇒ 
⇒ 

As,
⇒ 
then,
⇒ 
⇒ 