The answer is A
Materials that are good conductors of thermal energy are called thermal conductors. Metals are very good thermal conductors. Materials that are poor conductors of thermal energy are called thermal insulators. Gases such as air and materials such as plastic and wood are thermal insulators
Answer: 1160 m
Explanation:
Speed = distance / time. Plug in 40 m/s for speed and 29 s for time in order to get the distance, 1160 m.
Answer:
- The emf of the generator is 6V
- The internal resistance of the generator is 1 Ω
Explanation:
Given;
terminal voltage, V = 5.7 V, when the current, I = 0.3 A
terminal voltage, V = 5.1 V, when the current, I = 0.9 A
The emf of the generator is calculated as;
E = V + Ir
where;
E is the emf of the generator
r is the internal resistance
First case:
E = 5.7 + 0.3r -------- (1)
Second case:
E = 5.1 + 0.9r -------- (2)
Since the emf E, is constant in both equations, we will have the following;
5.1 + 0.9r = 5.7 + 0.3r
collect similar terms together;
0.9r - 0.3r = 5.7 - 5.1
0.6r = 0.6
r = 0.6/0.6
r = 1 Ω
Now, determine the emf of the generator;
E = V + Ir
E = 5.1 + 0.9x1
E = 5.1 + 0.9
E = 6 V
Answer:
Solution given:
No of waves[N] =20crests & 20 troughs
=20waves
Time[T]=4seconds
distance[d]=3cm=0.03m
Now
<u>Wave</u><u> </u><u>length</u><u>=</u>3cm=3 × 
<u>Frequency</u>=
=
=5Hertz
and
Wave speed:wave length×frequency=3 × ×5=1.5 × 
.
Answer: 39.8 μC
Explanation:
The magnitude of the electric field generated by a capacitor is given by:
d is the distance between the plates.
For a capacitor, charge Q = CV where C is the capacitance and V is the voltage.
where A is the area of the plate and ε₀ is the absolute permittivity.
substituting, we get
It is given that the magnitude of the electric field that can exist in the capacitor before air breaks down is, E = 3 × 10⁶ N/C.
radius of the plates of the capacitor, r = 69 cm = 0.69 m
Area of the plates, A = πr² = 1.5 m²
Thus, the maximum charge that can be placed on disks without a spark is:
Q = E×ε₀×A
⇒ Q = 3 × 10⁶ N/C × 8.85 × 10⁻¹² F/m × 1.5 m² = 39.8 × 10⁻⁶ C = 39.8 μC.
