**Answer:**

The correct options are:

**B) They have the same wave speed as visible light**

**D) They have a lower frequency than gamma rays.**

**Explanation:**

B) Ultraviolet rays, commonly known as UV rays, are a type of electromagnetic ways. As electromagnetic waves, in the layman's term, are all kinds of life that can be identified, all electromagnetic waves (UV rays, visible light, infrared, radio etc) all travel with the same velocity, that is the speed of light, given as **v = 3 × 10⁸ m/s**

D) The frequency of all electromagnetic rays can be found by electromagnetic spectrum (picture attached below).

We can clearly see in the picture that the frequencies of **UV rays lie at about 10¹⁵ - 10¹⁶ Hz **which is **lower** than the frequency of **Gamma ray, which lie at about 10²⁰ Hz.**

If the **maximum emf** of the **ac generator** is 20 V and the **maximum potential difference** across the **resistor** is 16 V Then the maximum potential difference across the **inductor** is 4 V.

**Calculation:**

**Step-1:**

It is given that the RL circuit is connected to a 20 V ac generator. The **maximum potential difference** across the **resistor** is 16 V. It is required to find the maximum potential drop across the **inductor**.

**Step-2:**

The **maximum emf** of the generator is equal to the sum of the maximum potential difference across the resistor and the maximum potential difference across the inductor.

Therefore,

The maximum potential difference across the inductor + Maximum maximum potential difference across the resistor = Maximum emf of the generator

Thus,

Maximum maximum potential difference across the inductor + 16 V = 20 V

Therefore,

Maximum maximum potential difference across the inductor = 20 V - 16 V = 4 V

Learn more about **potential differences **across **resistor **and **inductor **here,

brainly.com/question/15715072

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**Answer**

Radius of the Balloon = 12.5 m

the skin and the cargo of the balloon have a mass = 850 kg

Volume of balloon=

=

=8181.20 m³

Mass the ballon can carry= volume x [density of air-density of helium]

=8181.2 x [ 1.29 - 0.179 ]

=9089 kg

Mass of cargo = 9089 - 850

**= 8239 kg**

Answer:

Explanation:

From the question we are told that:

Velocity of both spaceships

Time

Generally the equation for time of spaceship 2 through earth is mathematically given by