공대생의 공부공간

문제)Plane-polarized light is incident on a single polarizing disk with the direction of E parallel to the direction of the transmission axis. Through what angle should the disk be rotated so that the intensity in the transmit ted beam is reduced by a factor of (a) 3.00.(b) 5.00.(c) 10.0. 풀이) (a) I reduced into 1 / 3.00 × I_max,I / I_max = 1 / 3.00 = cos^2 θ. cos θ = √(1 / 3.00).  θ = arccos √(1 /..

문제) A possible means of space flight is to place a perfectly reflecting aluminized sheet into orbit around the Earth and then use the light from the Sun to push this “solar sail.” Suppose a sail of area A = 6.00 × 10^5 m^2 and mass m = 6.00 × 10^3 kg. Ignore all gravitational effects and assume a solar intensity of 1370 W / m^2 (a) Calculate the force is exerted on the sail.(b) Calculate the sai..

Electromagnetic sinusoidal wave propagating in the x direction. Suppose the wave length is 50.0 m and the electric field vibrates in the xy plane with an amplitude of 22.0 V/m. (a) Calculate the frequency of the wave.(b) the magnetic field B when the electric field has its maximum value in the negative y direction.(c) Write an expression for B with the correct unit vector, with numerical values ..

문제) The switch is connected to position a for a long time interval. At t = 0, the switch is thrown to position b. After this time,(a) Calculate the frequency of oscillation of the LC circuit.(b) Calculate the maximum charge that appears on the capacitor (c) Calculate the maximum current in the inductor(d) the total energy the circuit possesses at t = 3.00 s 풀이)(a) the frequency of oscillation of..

문제) An electric field of 300 V/m is confined to a circular area d = 10.0 cm in diameter and directed outward perpendicular to the plane.If the field is increasing at a rate of 20.0 V/m·s, r = 15.0cm (a) Calculate the direction of the magnetic field at point P.(b) Calculate the magnitude of the magnetic field at the point P. 풀이)|E| = 300 V/m, d = 10.0 cm = 0.100 m, r = 15.0 cm = 0.150 mElectric f..

문제)A 0.900V potential difference is maintained across a 1.50m length of tungsten wire that has a cross-sectional area of 0.600mm^2. Calculate the current in the wire.  풀이)l = 1.50mA = 0.600mm^2 = 0.600 × 10^-6 m^2 = 6.00 × 10^-7 m^2△V = 0.900 V V = IR, I = V / R, R = ρ × l ÷ A임을 이용함. tungsten의 ρ(resistivity) = 5.6 × 10^-8 I = V / R = ( V × A ) / ( ρ × l ) I = ( V × A ) / ( ρ × l ) = ( 0.900 V × ..

문제)R = 1.00 MΩ, C = 5.00 μF, ε = 30.0 V (a) Calculate the time constant of the circuit(b) Calculate the maximum charge of the capacitor after the switch is closed(c) Calculate the current in the resistor 10.0s after the switch is closed  풀이)R = 1.00 MΩ = 1.00 × 10^6 ΩC = 5.00 μF = 5.00 × 10^-6 Fε = 30.0 V (a)time constant τ = RC τ = RC = 1.00 × 10^6 Ω × 5.00 × 10^-6 F = 5.00 s (b) the maximum ch..

문제)An air-core solenoid with 68 turns is 8.00cm long and has a diameter of 1.20cm. When the solenoid carries a current of 0.770A, how much energy is stored in its magnetic field within the solenoid? 풀이)magnetic field에 stored된 energy를 구하는 공식은 아래와 같다. U = 1/2 × I^2 × LL = μ0 × N^2 × A ÷ l μ0 = 4π × 10^-7 Tm/A N = 68l = 8.00 × 10^-2 mr = 1/2 × 1.20cm = 0.60cm = 6.00 × 10^-3 m A = π × r^2 = 36.0 × 1..

문제)위 그림과 같이 Magnetic field directed into the page changes with time according to B = 0.0300t^2 + 1.40. The field has a circular cross section of radius r = 2.50cm. When t = 3.00s and r2 = 0.0200m, (a) calculate the magnitude of the electric field at the point p2. (b) find the direction of the electric field at the point p2. 풀이)(a)p2에서 induced electric field는 다음과 같은 방법으로 구할 수 있다. E = - dB/dt × r2..

문제)위와 같이 회로가 구성되어 있고, R = 6.00 Ω, l = 1.20 m, |B| = 2.50 T라고 가정할 때 아래 두 문제를 풀어라.(a) Calculate the applied force requred to moce the bar to the right at a constant speed of 2.00 m/s.(b) At what rate is energy delivered to the resistor?. 풀이)(a) Φ = Blx임을 이용한다.또한 constant speed of 2.00 m/s로 움직이게 하는 applied force이므로, acceleration = 0이다. Bar을 일정한 속력 v로 움직이게 하는 것을 가정하고 있기 때문에 x = vt로 표현할 수 있다. 따라서 Φ =..