Thiết bị không phải nguồn điện:
Đáp án D
Answer:
Natural selection is a mechanism, or cause, of evolution.
Explanation:
Adaptations are physical or behavioral traits that make an organism better suited to its environment. Heritable variation comes from random mutations.
We are given:
v0 = initial velocity = 18 km/h
d = distance = 4 km
v = final velocity = 75 km/h
a =?
<span>
We can solve this problem by using the formula:</span>
v^2 = v0^2 + 2 a d
75^2 = 18^2 + 2 (a) * 4
5625 = 324 + 8a
<span>a = 662.625 km/h^2</span>
Answer:
Option (e)
Explanation:
A = 45 cm^2 = 0.0045 m^2, d = 0.080 mm = 0.080 x 10^-3 m,
Energy density = 100 J/m
Let Q be the charge on the plates.
Energy density = 1/2 x ε0 x E^2
100 = 0.5 x 8.854 x 10^-12 x E^2
E = 4.75 x 10^6 V/m
V = E x d
V = 4.75 x 10^6 x 0.080 x 10^-3 = 380.22 V
C = ε0 A / d
C = 8.854 x 10^-12 x 45 x 10^-4 / (0.080 x 10^-3) = 4.98 x 10^-10 F
Q = C x V = 4.98 x 10^-10 x 380.22 = 1.9 x 10^-7 C
Q = 190 nC
Answer:
(a) 
(b) neither increasing or decreasing
(c) opposite to the flow of charge carriers
Explanation:
The current through an inductor of inductance L is given by:
(1)
(a) The induced emf is given by the following formula
(2)
You derivative the expression (1) in the expression (2):
(b) At t=0 the current is zero
(c) At t = 0 the emf is:
w, L and Imax have positive values, then the emf is negative. Hence, the induced emf is opposite to the flow of the charge carriers.
(d) read the text carefully
