Question

Help!

Answer 1

$\qquad\qquad\huge\underline{{\sf Answer}}$

As we know, period (t)of a wave and it's frequency (f) are Reciprocal of each other, so if one is know then we can just reverse the order to get the other one.

that is :

$\qquad \sf \dashrightarrow \: frequency = \dfrac{1}{period}$

Now, let's move on to problems ~

# 11. f = 15 hertz, t = ?

$\qquad \sf \dashrightarrow \: t = \dfrac{1}{15} \: \: sec$

$\qquad \sf \dashrightarrow \: t \approx0.067 \: \: sec$

#12. f = 292 hertz, t = ?

$\qquad \sf \dashrightarrow \: t = \dfrac{1}{292} \: \: sec$

$\qquad \sf \dashrightarrow \: t \approx0.0034 \: \: sec$

#13. t = 12 seconds, f = ?

$\qquad \sf \dashrightarrow \: f= \dfrac{1}{12} \: \: hertz$

$\qquad \sf \dashrightarrow \: f \approx0.083 \: \: hertz$

Answer 2

$\huge\underline{\underline{\mathbb{A\:N\:S\:W\:E\:R}}}$

We know that, frequency = reciprocal of the period of time an object swings or vibrates at. Therefore,

$\tt\:FORMULA \downarrow\\\\\star\boxed{\mathfrak{Frequency = \frac{1}{period \: of \: time}}}$

Now, let's solve the questions by using this formula.

$\rule{150pt}{2pt}$

11. Frequency = 15 Hz

Period = ?

$\sf\:Frequency = \frac{1}{period}\\\sf\:15 = \frac{1}{period}\\\boxed{\bf\:period = \frac{1}{15} = 0.67 \: s}$

$\rule{150pt}{2pt}$

12. Frequency = 292 Hz

Period = ?

$\sf\:Frequency = \frac{1}{period}\\\sf\:292 = \frac{1}{period}\\\boxed{\bf\:period = \frac{1}{292} = 0.0034 \: s}$

$\rule{150pt}{2pt}$

13. Period = 12 s

Frequency = ?

$\sf\:Frequency = \frac{1}{period}\\\sf\:Frequency = \frac{1}{12}\\\boxed{\bf\:Frequency = 0.083 \: Hz}$

$\rule{150pt}{2pt}$

Note:

The SI units of,

• Frequency = Hertz (Hz)
• Period of time = Second (s / sec)

$\rule{150pt}{2pt}$