Answer:
20 seconds
Explanation:
The equation for Power is:
Which means...
We can plug in the given values into the equation:
Answer:
ΔE = 8.77 × 10¹¹ J
Explanation:
given,
²¹⁴₈₄Po -----> ²¹⁰₈₂Pb + 42 He
Atomic masses: Pb-210 = 209.98284 amu
Po-214 = 213.99519 amu
He-4 = 4.00260 amu
1 kg = 6.022 × 10²⁶ amu;
NA = 6.022 × 10²³ mol⁻¹
c = 2.99792458 × 10⁸ m/s
energy of molecule using equation
ΔE = Δm c²
Δm is mass difference and c is speed of light
Δm = 209.98284 + 4.00260 - 213.99519
Δm = - 0.00975 amu
1 amu = 1.66 x 10⁻²⁷ kg
- 0.00975 amu = - 0.00975 x 1.66 x 10⁻²⁷ Kg
= -0.016185 x 10⁻²⁷ Kg
total mass = 6.022 × 10²³ x -0.016185 x 10⁻²⁷
= -0.097467 x 10⁻⁴ Kg
ΔE = -(0.097467 x 10⁻⁴) (3 x 10^8)²
ΔE = - 8.77 × 10¹¹
ΔE = 8.77 × 10¹¹ J
B.temperature is an indirect measurement of the heat energy in a substance
Answer:
1.) 10.61 A
2.) 0.27 A
Explanation:
Given that a sinusoidal A.C has a maximum value of 15A.
1) What are its r.m.s values?
ii) If the time is recorded from the instant the current is zero and is becoming
positive, what is the instantaneous value of the current after 1/300s, given the
frequency is 50 Hz.
Solution.
1.)
The r.m.s current = peak current/root 2
The r.m.s current = 0.7071 × 15
The r.m.s current = 10.61 A
2.)
Given that
Time = 1/300 s
Frequency = 50 Hz
Instantaneous current can be calculated by using the formula
I = I sin wt
Where w = 2πf
Instantaneous current = 15( sin 2πft)
I = 15 × sin ( 2 × 3.143 × 50 × 1/300 )
I = 15 × sin ( 1.047 )
I = 15 × 0.01827
I = 0.27 A
Therefore, the instantaneous current is 0.27A
Answer:
2.551 m/s
Explanation:
Given:
Boulder is dropped from the cliff
thus,
Initial speed of the boulder, u = 0 m/s
Final speed to be obtained, v = 90 km/h =
=25 m/s
also, in the case of free fall the acceleration of the boulder will be equal to the acceleration due to the gravity i.e g = 9.8 m/s²
Now, from the Newton's equation of motion
v = u + at
where, a is the acceleration = g = 9.8 m/s²
t is the time
on substituting the respective values, we get
25 = 0 + 9.8 × t
or
t = 
or
t = 2.551 m/s
