Answer:
why compasses point towards the north and south poles of the earth.
Explanation:
hope it helps!!
 
        
             
        
        
        
Explanation:
(a)
Critical angle is the angle at the angle of refraction is 90°. After the critical angle, no refraction takes place.
Using Snell's law as:
 
Where,  
 is the angle of incidence
  is the angle of incidence 
 is the angle of refraction = 90°
 is the angle of refraction = 90°
 is the refractive index of the refraction medium
 is the refractive index of the refraction medium 
 is the refractive index of the incidence medium
 is the refractive index of the incidence medium 
Thus, 
 
The formula for the calculation of critical angle is:
 
Where,  
 is the critical angle
 is the critical angle
(b) 
No it cannot occur. It only occur when the light ray bends away from the normal which means that when it travels from denser to rarer medium.
 
        
             
        
        
        
Answer:
T₂ = 95.56°C
Explanation:
The final resistance of a material after being heated is given by the relation:
R' = R(1 + αΔT)
where,
R' = Final Resistance = 207.4 Ω
R = Initial Resistance = 154.9 Ω
α = Temperature Coefficient of Resistance of Tungsten = 0.0045 °C⁻¹
ΔT = Change in Temperature = ?
Therefore,
207.4 Ω = 154.9 Ω[1 + (0.0045°C⁻¹)ΔT]
207.4 Ω/154.9 Ω = 1 + (0.0045°C⁻¹)ΔT
1.34 - 1 = (0.0045°C⁻¹)ΔT
ΔT = 0.34/0.0045°C⁻¹
ΔT = 75.56°C
but,
ΔT = Final Temperature - Initial Temperature
ΔT = T₂ - T₁ = T₂ - 20°C
T₂ - 20°C = 75.56°C
T₂ = 75.56°C + 20°C
<u>T₂ = 95.56°C</u>
 
        
             
        
        
        
In comparison to a distribution with a standard deviation of 5, one has a curve with a higher peak. The variability will be greater the larger the standard deviation. It denotes increased variability in a distribution with a standard deviation of 5.
<h3>What do you mean by the term standard deviation?</h3>
The term "standard deviation" (or "") refers to a measurement of the data's dispersion from the mean. A low standard deviation implies that the data are grouped around the mean, whereas a large standard deviation shows that the data are more dispersed. In contrast, a high or low standard deviation indicates that the data points are, respectively, above or below the mean. A standard deviation that is close to zero implies that the data points are close to the mean. the curve at the top is more dispersed and has a greater standard deviation than the curve at the bottom, which is more concentrated around the mean and has a lower standard deviation.
To learn more about standard deviation, Visit:
brainly.com/question/14650840
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Answer:
3.71 m/s
Explanation:
From the law of conservation of linear momentum, since we are neglecting minor energy losses due to friction then we can express it as  since all the potential energy is transformed to kinetic energy
 since all the potential energy is transformed to kinetic energy
Making v the subject of the formula then  and here m is the mass of the block, g is acceleration due to gravity, h is the height. Substituting 0.7 m for h and 9.81 for g then we obtain that
 and here m is the mass of the block, g is acceleration due to gravity, h is the height. Substituting 0.7 m for h and 9.81 for g then we obtain that 