Answer:
Explanation: the major difference between an electromagnet and permanent magnet is that the former can have a magnetic field when electric current flows through it and disappears when the flow of the current stops. ... It will always displays the magnetic behaviour.
Answer:
The possible frequencies for the A string of the other violinist is 457 Hz and 467 Hz.
(3) and (4) is correct option.
Explanation:
Given that,
Beat frequency f = 5.0 Hz
Frequency f'= 462 Hz
We need to calculate the possible frequencies for the A string of the other violinist
Using formula of frequency
...(I)
...(II)
Where, f= beat frequency
f₁ = frequency
Put the value in both equations
Hence, The possible frequencies for the A string of the other violinist is 467 Hz and 457 Hz.
Answer: i think c
Explanation:QA: “What is ordinary glass made of ?”
Glass is mostly silica, or silicon dioxide, present as quartz in many types of sand. Pure silica forms a highly transparent glass, but has a very high melting or softening temperature, around 1700°C. Even at such high temperatures it is highly viscous and difficult to work. Its use is largely confined to applications requiring high transparency to ultra-violet and infra-red radiation, stability at elevated temperatures or low thermal expansion coefficient.
“Ordinary glass” windows and drinking vessels are typically made from soda-lime glass, containing silica with around 25% sodium, calcium and other oxides, which together reduce the softening temperature to roughly 500–600°C
