1.
An air-filled parallel-plate capacitor has plates of area 2.30 cm?separated by 1.50 mm. The capacitor is connected to a 12.0 V battery.What is the charge on the capacitor?
2.
A myelinated segment of the axon has a radius of 2×10-⁶m and a length of 1 cm. Find its membrane capacitance and its membrane leakage resistance,If the Resistance of a unit area of the myelinated axon membrane Rm =40 Ω. m? and the Capacitance of a unit area of the myelinated axon membrane Cm = 5 x 10‐⁵ f/m²
A.
6. 28 x 10-12 f/ 3. 18 x 10⁸ Ω
B.
3. 18 x 10⁸f / 1.59 x 10⁶ Ω
C.
3. 18 x 10⁶ f / 1.59 x 10⁸ Ω
D.
6. 28 x 10‐¹² f/3.18 x 10⁸Ω
3.
What is the space parameter for an axon of radius 3×10-⁶m if it is myelinated axon ( R_{m} = 40 Ω .m²,ρ= 2
4.
A myelinated axon has a space parameter of 1 cm. Find its radius .
( R_{m} = 40 2Ω. m²,ρ = 2 Ω.m)
5.
A square meter of the axon membrane has a resistance of 0.2 ohms. The
membrane is 7.5 x 10‐⁹ m thick. What is the resistivity of the membrane?
6.
When a potential difference of 150 V is applied to the plates of a parallel-plate capacitor, the plates carry a surface charge density of 30.0 nc/m². What is the spacing between the plates?
7.
Two small metallic spheres, each of mass m = 0.200 g, are suspended as pendulums by light strings of length L as shown in Figure. The spheres are given the same electric charge of 7.2 nC and they come to equilibrium when each string is at an angle of θ = 5.00° with the vertical. How long are the strings?
8.
Calculate the current through a 10.0 m long Nichrome wire (the radius is 0.321 mm ) if it is connected to a 12.0 V battery.(The resistivity of nichrome is 100 ×10^{-}⁸ Ω.m)
9.
In the figure, a uniform electric field that has a magnitude of 4x10⁴ V/m. if the separation between points A and B is 0.5 m, calculate the change in electric potential between points A and B, (VB-VA).
10.
A conductor of radius r, length L and resistivity p has resistance R. what is the new resistance if it is stretched to 4 times its original length
tip: Volume remains constant
11.
Suppose that you have two charged particles. of different charges, (magnitude and sign)
your friend claims that the symmetry is broken if the charges are not of equal magnitude.
Meaning that the string would make two different angles with the Vertical.
What do you think?
12.
The percentage of radiation absorbed during total internal reflection is
13.
Calculate the resistance of an aluminum cylinder ( resistivity of
aluminum is 2. 82 × 10−6 Ω. m ) that is 10 cm long and has a cross sectional
area of 2 × 10−4 m2
.
14.
When light is normally incident in air ( with refractive index 1.0) on a surface , 6 percent of the intensity is reflected . What is the index of refraction of the material
15.
The wavelength of red helium – neon laser in air is 632.8 nm. What is its period? ( speed of light in air is C = 3 * 10^{8} m/s.
16.
- A ray through the center of the lens emerges
A.
Parallel to the optic axis behind the lens .
B.
Refracted through focal point front the lens
C.
D.
Deflected through focal point behind lens
17.
The image in the concave lens is always
18.
Al lens has focal length of 1.5m . A virtual objects placed 0.5 m from the lens . What is the magnification.
A.
-0.53 (inverted , reduced )
B.
5.3 (up right , enlarged )
C.
-2.5 ( inverted , reduced )
D.
0.25 ( up right , enlarged )
19.
A lens has a focal length of 1.5 m . When a second lens is placed in contact the pair has a focal length of 1.0 m . What is the focal length of the second lens ?
20.
Convex lens has -------- radios , concave lens has -------- radios
21.
The distance between two successive peaks of a sinusoidal wave travelling along a string in 3m,If the frequency of this wave is 6 Hz,what is the speed of this wave?
22.
A speaker emits sound waves into the air (speed the sound in air is 340m/s) with a wave length of a 0.07 for 0.4 second. How many complete waves are emitted in this time interval?
23.
Whale can locate a largest of 8cm height about 120m away. If the ΔPmax=30 pa. what is the percentage functional density if the bulk modulus of water is 2.1* 10^{9 }N/m^{2}?
24.
What is the intensity of a sound that is 15dB louder than that of sound intensity 1∗10^{-8} w/m2?
25.
The average cross-sectional area of a woman’s femur is 10^{-3} m^{2} and it is 0.4 m long. The woman weights 750N . assuming the stress-strain relationship is linear until fracture, what is change in length just prior to fracture(young’s modulus for bone under compression= 0.9 * 10^{9} N/m^{2} and the ultimate compression strength for bone is 17* 10^{7} N/m^{2}) ?