لمّاح✨ SEU

كل متطوع يصور درجته

Question 31 Question: Heat absorbed from the hot reservoir is $500\text{ J}$ and heat rejected to the cold reservoir is $200\text{ J}$. What is the efficiency of the engine? Answer: B - 60%

Question 21 Question: Determine electrical potential at a point $0.40\text{ m}$ from a $+30\ \mu\text{C}$ point charge? Answer: A - $6.75\times10^5\text{ V}$ Question 22 Question: A potential difference of $150\text{ V}$ is applied to two parallel metal plates. If an electric field of $2000\text{ V/m}$ is produced between the plates, how far apart are the plates? Answer: A - $\text{d}= 0.075\text{ m}$ Question 23 Question: If a $14\text{ V}$ battery has a charge of $20\text{ C}$ then the chemical energy in the battery is Answer: A - $280\text{ Joules}$ Question 24 Question: Assume an area $\text{A}= 6\times10^{-7}\text{ m}^2$ and resistivity of a gold wire is $2.44\times10^{-8}\ \Omega\cdot\text{m}$, find the length $\text{L}$ of the gold wire which is required to produce a resistance of $0.3\ \Omega$. Answer: B - $7.40\text{ m}$ Question 25 Question: If the current through $10\ \Omega$ lamp is $16\text{ A}$, Find the operating voltage? Answer: C - $160\text{ V}$ Question 26 Question: An electric heater draws a current of $12\text{ A}$ on a $120\text{ V}$ line. Find the power consumed in the heater? Answer: C - $14440\text{ W}$ Question 27 Question: In series combinations of resistors, the current I is different in all resistors. Answer: False Question 28 Question: Magnetic force is dependent on the velocity and motion of a charged particle. Answer: True Question 29 Question: The equivalent resistance of resistors connected in parallel is always greater than the largest individual resistor. Answer: False Question 30 Question: The electric field always exerts an electric force on a charged particle even if it is stationary. Answer: True

Question 11 Question: The sound has intensity $10^{-8}\text{ W/m}^2$. What is sound level? Answer: C - 40 dB Question 12 Question: The linear density of a string is given as Answer: D - $\mu/\text{L}$, L is the length of string Question 13 Question: What is the speed of light in a cubic zirconia with an index of refraction of 2.2 if the speed of light on Vacuum $c = 3 \times 10^8\text{ m/s}$ Answer: D - $1.36 \times 10^8\text{ m/s}$ Question 14 Question: The refracted light vanishes at the critical angle and the reflection becomes ........... for any angle $\theta_1 > \theta_{\text{critical}}$ Answer: D - 100% Question 15 Question: Metals are poor thermal conductors Answer: False Question 16 Question: Specular reflection of light occurs when the light incidents a reflective surface such as mirror. Answer: True Question 17 Question: Isothermal expansion means no heat absorbed. Answer: False Question 18 Question: A mixture of ice and water at atmospheric pressure is the steam point of water. Answer: False Question 19 Question: The light carries momentum. Answer: True Question 20 Question: In oscillatory motion, the displacement and restoring force always point in the same direction. Answer: False

النموذج الثاني 🚨 Question 1 Question: The increase in the size of an object with an increase in its temperature is Answer: A - thermal expansion Question 2 Question: Absolute zero is equal to Answer: B - -273.15 °C Question 3 Question: Amount of energy needed to raise the temperature of the sample by 1°C is Answer: C - Heat capacity Question 4 Question: ... and rejects 200 J to a cold reservoir. What is its efficiency? Answer: B - 60% Question 5 Question: An engine transfers 2000 J of energy from a hot reservoir during a cycle and transfers 600 J as exhaust to a cold reservoir. Calculate the work of this engine in one cycle? Answer: C - 1400 J Question 6 Question: Calculate the thermal efficiency of a heat engine that gains 2000 J of energy and loses 400 J during one period Answer: B - 80% Question 7 Question: As a person runs towards the speaker, the frequency he hears Answer: D - Higher Question 8 Question: diffraction of light occurs when the light passes through the opening in a barrier (d) which has the following condition Answer: A - d = $\lambda$ Question 9 Question: When a ray of light enters a medium, the velocity of light becomes $2.3 \times 10^8\text{ m/s}$. Determine the refractive index of the medium. (Hint: speed of light in vacuum $c = 3.00 \times 10^8\text{ m/s}$) Answer: A - 1.3 Question 10 Question: If the wave number of a certain wave is $12.00\text{ m}^{-1}$, and the frequency is $4.00\text{ Hz}$. The speed of the wave is: Answer: D - 0.66 m/s