Buzztutor Questions and Answers by Category

3701

Physics Heat & Thermodynamics Level: University

Heat
If 120 g of hot coffee at 85 C is poured into an insulated cup containing 200 g of ice (a) How many grams of liquid will there be when the system reaches thermal equilibrium.
(b) How much ice will remain

3700

Physics Heat & Thermodynamics Level: University

If the energy that goes onto evaporating 1kg of water from a lake were used instead to raise that same kg into the air how high would the water be raised?

3699

Physics Heat & Thermodynamics Level: University

Heat
An iron bar is exactly 1 meter long at 15 degree celcius. A brass bar is 0.5 mm shorter at the same temperature. At what temperature will they be the same lengths if they are heated simultaneously.

3698

Physics Heat & Thermodynamics Level: University

3697

Physics Heat & Thermodynamics Level: University

Heat
A steel plate with a circular hole 2.01 cm in radius and a copper ball with a radius of 2 cm are initially at 15 degree celcius . If their temperature is raised to 275 degree celcius , will the ball still fit through the hole?

3696

Physics Magnetism,Magnetic Effects Of Current Level: University

Magnetic effect of current
A wire carries a current of 22 A from east to west. Assume that at this location the Earth s magnetic field is horizontal and directerd from south to north. The magnitude of the field at this location is 500 u T. Find the magnitude and direction of the magnetic force on a 36-m lenght of wire in this field. How does the force change if the current runs from west to east?

3695

Physics Alternating Current Level: University

Transformers
A step - up transformer is designed to have an out put of 2200 V when the primary is connected across a 110-V source. If there are 80 turns in the primary how many turns are required on the secondary? If a load resistor across the secondary draws a current of 1.5 A, what is the current in the primary?

3694

Physics Electromagnetic Induction Level: University

A coil with25 turns of wire is would on a square frame 1.80 cm on a side. Each turn of wire has the same area equal to that of the frame and the total resistance of the coil is 0.35 ohms. A uniform magnetic field is applied perpendicular to the plane of the coil. If the field changes uniformly from 0 to 0.500 T in 0.800 s find the magnitude of the induced emf in the coil while the field is changing.

3693

Physics Ray Optics Level: University

Intensity & distance
The intensity of a spherical wave is 4.0 m from the source is 120 w/m^2. What is the intensity at a point 9.0 m from the source?
(a) 11 w/m^2
(b) 24 w/m^2
(c) 53 w/m^2
(d) 80 w/m^2
(e) 270 w/m^2

3692

Physics Waves And Oscillations Level: University

Speed of sound
A physics student is asked to determine the length of a long slender cooper rod by measuring the time required for the sound pulse to travel the length of the rod. The young s modulus of cooper is 1.1 x 10^11 N/m^2 and its density is 8890 kg/m^3. The student finds that the time for the pulse to travel from one end to the other is 1.56 X 10^-3 s. How long is the rod.
(a) 0.18 m
(b) 1.2 m
(c) 5.5 m
(d) 19 m
(e) 31 m