The period of a wave is equal to the time it takes for one wavelength to pass by a ﬁxed point. You stand on a pier watching water waves and see 10 wavelengths pass by in a time of 40 seconds

3 0

3 years ago

the internal energy of an object has two parts: internal potential energy of its molecules and the kinetic energy of those molec

BARSIC [14]

The most appropriate answer is B !! No heat flow as there is no difference in temp between them !!

8 0

3 years ago

A tungsten wire has resistance R at 20°C. A second tungsten wire at 20°C has twice the length and half the cross-sectional area

Colt1911 [192]

Answer:

Resistance will become 4 times of first wire resistance.

Explanation:

At the temperature of both the the tungsten wire is same so we can apply ohm's law

Let the length of first wire is $l_1$ and cross sectional area is $A_1$

Resistance of first wire $R=\frac{\rho l_1}{A_1}$ ......1

Now length of second wire is twice the length of first wire

$l_2=2l_1$ and cross sectional area $A_2=\frac{A_1}{2}$ .......2

Resistance of wire 2 $R_2=\frac{\rho l_2}{A_2}$ ........2

Dividing equation 1 by equation 1

$\frac{R}{R_2}=\frac{\rho l_1}{A_1}\times \frac{0.5A_1}{\rho 2l_1}$

$R_2=4R$

Therefore resistance will become 4 times.

8 0

3 years ago