2 years ago

what will be the focal lenght of a combined lens made by contact of two lenses of power +3D and -2D.

Physics

1 answer:

4vir4ik [10]2 years ago

3 0

P_1=+3D
P_2=-2D

$\\ \bull\tt\dashrightarrow P=P_1+P_2$

$\\ \bull\tt\dashrightarrow P=+3D-2D=+1D$

Now

$\\ \bull\tt\dashrightarrow f=\dfrac{1}{P}$

$\\ \bull\tt\dashrightarrow f=\dfrac{1}{1}$

$\\ \bull\tt\dashrightarrow f=1m$

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Find the length (in m) of an organ pipe closed at one end that produces a fundamental frequency of 494 Hz when air temperature i

elena-14-01-66 [18.8K]

Answer:

0.173 m.

Explanation:

The fundamental frequency of a closed pipe is given as

fc = v/4l .................. Equation 1

Where fc = fundamental frequency of a closed pipe, v = speed of sound l = length of the pipe.

Making l the subject of the equation,

l = v/4fc ................ Equation 2

also

v = 331.5×0.6T ................. Equation 3

Where T = temperature in °C, T = 18.0 °c

Substitute into equation 3

v = 331.5+0.6(18)

v = 331.5+10.8

v = 342.3 m/s.

Also given: fc = 494 Hz,

Substitute into equation 2

l = 342.3/(4×494)

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l =0.173 m.

Hence the length of the organ pipe = 0.173 m.

7 0

3 years ago

Two parallel wires carry a current I in the same direction. Midway between these wires is a third wire, also parallel to the oth

Luda [366]

Answer:

Force is repulsive hence direction of force is away from wire

Explanation:

The first thing will be to draw a figure showing the condition,

Lets takeI attractive force as +ve and repulsive force as - ve and thereafter calculating net force on outer left wire due to other wires, net force comes out to be - ve which tells us that force is repulsive, hence direction of force is away from wire as shown in figure in the attachment.