The type of current produced by a battery is direct current. C.
In question 1, both of your answers are correct, but I don't understand the process you went through in the 'a' part.
R = v/I . That's a correct formula.
But it doesn't help you in this form, because you need to find I
So turn it into a helpful form ... Solve it for I, so it says I=something.
R= v/I
Multiply each side by I : R I = V.
Now divide each side by R: I= V/R .
THERE'S the equation you want.
I = V / R
I = 1.5 / 10 = 0.15 Amp.
That's slightly cleaner, although I don't really understand what you were actually thinking in that part.
But again ... You answered both parts correctly, and your process in b is fine.
Answer:
Explanation:
No of atoms of Ra in 1 g of sample = 6.023 x 10²³ / 226
N = 2.66 x 10²¹
disintegration constant λ = .693 / half life
half life = 1620 x 365 x 60 x 60 x 24 = 5.1 x 10¹⁰ s
disintegration constant λ = .693 / 5.1 x 10¹⁰
radioactivity dn / dt = λN
= (.693 / 5.1 x 10¹⁰ ) x 2.66 x 10²¹
= .3614 x 10¹¹ per sec
= 3.614 x 10¹⁰ / s
The Answer Is : D. 20.0 cm
My Reason : These types of problems can all be solved using the lens or mirror equation.
1/20 +1/q= 1/10
q=20 cm
The image is formed behind the lens at 2f or the center of curvature.
It is real, inverted, and the same size as the object
