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3 years ago

Unlike mechanical waves such as sound or earthquake waves, EM waves can travel through empty space. True or false

Physics

1 answer:

Alex777 [14]3 years ago

5 0

Answer:

its true

Explanation:

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Carbon-14 has a half-life of 5730 years after how many half lives will 120 g of carbon-14 decay to 15 g

lana [24]

The correct answer would be C. three half lives.

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3 years ago

When a bat uses echolocation to determine the distance to an insect, it sends out a sound wave and waits to see how long the sou

ZanzabumX [31]

Answer:

Explanation:

Distance travelled by sound in going to target( insect ) and returning back = 2d ,d is distance of target .

time t = .06 s

speed = distance / time

344.9 = 2d / .06

d = 10.35 m

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4 years ago

An elastic conducting material is stretched into a circular loop of 9.65 cm radius. It is placed with its plane perpendicular to

Nadya [2.5K]

Answer:

The induced emf in the coil is 0.522 volts.

Explanation:

Given that,

Radius of the circular loop, r = 9.65 cm

It is placed with its plane perpendicular to a uniform 1.14 T magnetic field.

The radius of the loop starts to shrink at an instantaneous rate of 75.6 cm/s , $\dfrac{dr}{dt}=-0.756\ m/s$

Due to the shrinking of radius of the loop, an emf induced in it. It is given by :

$\epsilon=\dfrac{-d\phi}{dt}\\\\\epsilon=\dfrac{-d(BA)}{dt}\\\\\epsilon=B\dfrac{-d(\pi r^2)}{dt}\\\\\epsilon=2\pi rB\dfrac{dr}{dt}\\\\\epsilon=2\pi \times 9.65\times 10^{-2}\times 1.14\times 0.756\\\\\epsilon=0.522\ V$

So, the induced emf in the coil is 0.522 volts.

8 0

3 years ago

An air-traffic controller observes two aircraft on his radar screen. The first is at altitude 850 m, horizontal distance 19.1 km

olya-2409 [2.1K]

Answer:

s = 3.69 km

Explanation:

given,

altitudes of the aircraft

h₁ = 0.85 km , h₂ = 1.3 km

position vector of the first plane is

$s_1 = 19.1 cos 25.5^0 \hat{i} + 19.1 sin 25.5^0 \hat{j} + 0.85 \hat{k}$

$s_1 = 17.24 \hat{i} + 8.22 \hat{j} + 0.85 \hat{k}$

position vector of the second plane is

$s_2 = 17.6 cos 15^0 \hat{i} + 17.6 sin 15^0 \hat{j} + 1.3 \hat{k}$

$s_2= 17 \hat{i} + 4.56 \hat{j} + 1.3 \hat{k}$

net displacement is

$s = s_2 - s_1$

= $17. \hat{i} + 4.56 \hat{j} + 1.3 \hat{k} - (17.24 \hat{i} + 8.22 \hat{j} + 0.85 \hat{k})$

= $-0.24 \hat{i} - 3.66 \hat{j} +0.45 \hat{k}$

magnitude is

$s = \sqrt{-0.24^2+(-3.66)^2+0.45^2}$

s = 3.69 km

8 0

3 years ago

Countries establish internal economic zones in order to

Delvig [45]

have fewer economic restrictions

Explanation:

3 0

4 years ago