(a) 25lx
(b) 11.11lx
<u>Explanation:</u>
Illuminance is inversely proportional to the square of the distance.
So,

where, k is a constant
So,
(a)
If I = 100lx and r₂ = 2r Then,

Dividing both the equation we get

When the distance is doubled then the illumination reduces by one- fourth and becomes 25lx
(b)
If I = 100lx and r₂ = 3r Then,

Dividing equation 1 and 3 we get

When the distance is tripled then the illumination reduces by one- ninth and becomes 11.11lx
Answer:
U = √Rg/sin2θ
Explanation:
Using the formula for "range" in projectile motion to derive the average speed before the ball hits the ground.
Range is the distance covered by the body in the horizontal direction from the point of launch to the point of landing.
According to the range formula,
R = U²sin2θ/g
Cross multiplying we have;
Rg = U²sin2θ
Dividing both sides by sin2θ, we have;
U² = Rg/sin2θ
Taking the square root of both sides we have;
√U² = √Rg/sin2θ
U = √Rg/sin2θ
Therefore, his average speed if he is to meet the ball just before it hits the ground is √Rg/sin2θ
Answer: option D) 42.4 N
The weight of the frame is balanced by the vertical component of tension.
W = T sin θ + T sin θ = 2 T sin θ
The tension in each cable is T = 30 N
Angle made by the cables with the horizontal, θ = 45°
⇒ W = 2×30 N × sin 45° = 2 × 30 N × 0.707 = 42.4 N
Hence, the weight of the frame is 42.4 N. Correct option is D.
Answer:
Explanation:
The correct answer is option C.
When the battery is operating a remote control toy the energy is converted from potential energy to the kinetic energy.
A battery stores electrical potential from the chemical reaction.
When the circuit is connected to the potential energy of the battery helps in the movement of the toy.
The energy produced by the movement of the control toy is kinetic energy.
Hence, we can say that Potential energy is changed to kinetic energy
<h3>
Answer:</h3><h3>we can say that:-</h3>
- A reading with more no of significant figures is considered to be more precise.
- Kyra recorded a reading of 24.3 sec. Since all non 0 digits are considered to be significant this reading has 3 significant figures.
- Pari recorded a reading of 24 sec. Since all non 0 digits are considered to be significant this reading has 3 significant figures.
<h3>hence we can say that kyra's reading has more significant figures nd so it is more precise.</h3>