Questions
Calculate the change in Entropy

A 288 kg block of ice at 0∘C is placed in a large lake the temperature of the lake is just slightly higher than 0∘C and the ice melts very slowly.

 

i) what is the entropy change of ice

 

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Magnification of a given lens.

What magnification will be produced by a lens of power –4.00 D (such as might be used to correct myopia) if an object is held 29 cm away?

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A point charge Q is placed at the center of a cube of side L. What is the flux through one face of the cube?

A point charge Q is placed at the center of a cube of side L. What is the flux through one face of the cube?

 

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Resistance of copper wire.

What is the resistance of a 2.9-m length of copper wire 1.4 mm in diameter? The resistivity of copper is 1.68×10−⁸Ω⋅m.

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How many electrons did it lose in the process of acquiring this charge?

When a honeybee flies through the air it develops a charge of +20pC. How many electrons did it lose in the process of acquiring this charge? Express answer as a number

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When Susan rides her bike, the distance that she travels varies directly with the amount of time she is biking. Suppose she bikes 50 miles in 2.5 hours. At this rate, how many hours would it take her to bike 80 miles?

When Susan rides her bike, the distance that she travels varies directly with the amount of time she is biking. Suppose she bikes 50 miles in 2.5 hours. At this rate, how many hours would it take her to bike 80 miles?

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A gas sample enclosed in a rigid metal container at room temperature (20.0∘C) has an absolute pressure p1. The container is immersed in hot water until it warms to 40.0∘C. What is the new absolute pressure p2?

Part A

A gas sample enclosed in a rigid metal container at room temperature (20.0∘C) has an absolute pressure p1. The container is immersed in hot water until it warms to 40.0∘C. What is the new absolute pressure p2?

Express your answer in terms of p1.

p2 =

1.0682p1

Part B

Nitrogen gas is introduced into a large deflated plastic bag. No gas is allowed to escape, but as more and more nitrogen is added, the bag inflates to accommodate it. The pressure of the gas within the bag remains at 1.00 atm and its temperature remains at room temperature(20.0∘C). How many moles n have been introduced into the bag by the time its volume reaches 22.4 L?

Express your answer in moles.

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In the figure below, two semicircular arcs have radii R2 = 7.90 cm and R1 = 2.75 cm, carry current i = 0.281 A, and share the same center of curvature C.

In the figure below, two semicircular arcs have radii R2 = 7.90 cm and R1 = 2.75 cm, carry current i = 0.281 A, and share the same center of curvature C.

(a) What is the magnitude of the net magnetic field at C?
______T

(b) What is the direction of the net magnetic field at C?
out of page or into page

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A glass marble is rubbed against a piece of silk. As a result the piece of fabric acquires extra electrons

A glass marble is rubbed against a piece of silk. As a result the piece of fabric acquires extra electrons. What happens to the glass marble? (Select all that apply)
The marble has lost the same number of electrons acquired by the piece of silk.
The marble acquires a positive charge and repels the piece of silk.
The marble acquires a negative charge and attracts the piece of silk.
The marble has acquired the same number of electrons acquired by the piece of silk.
The marble acquires a positive charge and attracts the piece of silk.
The marble acquires a negative charge and repels the piece of silk.

 

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Rank each satellite based on the net force acting on it. Rank from largest to smallest.

Rank each satellite based on the net force acting on it. Rank from largest to smallest.

  • 1. m= 100kg, L = 2500m, v= 160 m/s
  • 2. m= 300kg L = 10000m, v= 80 m/s
  • 3. m = 400kg L = 2500m, v= 80 m/s
  • 4. m = 200kg L = 5000m, v= 160 m/s
  • 5. m = 800kg L = 10000m, v= 40 m/s
  • 6. m = 200kg L = 5000m, v= 120 m/s

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The figure below shows a cross section across a diameter of a long cylindrical conductor

The figure below shows a cross section across a diameter of a long cylindrical conductor of radius a = 2.00 cm carrying uniform current 159 A. What is the magnitude of the current's magnetic field at the following radial distances?

(a) 0
_____ T

(b) 1.20 cm
_____ T

(c) 2.00 cm (wire's surface)
______ T

(d) 3.90 cm
______ T

 

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The two 10-cm-long parallel wires in the figure are separated by 5.0 mm.

The two 10-cm-long parallel wires in the figure are separated by 5.0 mm. For what value of the resistor R will the force between the two wires be 1.1×10−4 N ?

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What visible wavelengths of light are strongly reflected from a 390-nm-thick soap bubble?

A soap bubble is essentially a thin film of water surrounded by air. The colors you see in soap bubbles are produced by interference. What visible wavelengths of light are strongly reflected from a 390-nm-thick soap bubble? What color would such a soap bubble appear to be?

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A cylindrical beaker of height 0.100 m and negligible weight is filled to the brim with a fluid of density ρ = 890 kg/m3 . When the beaker is placed on a scale, its weight is measured to be 1.00 N

A cylindrical beaker of height 0.100 m and negligible weight is filled to the brim with a fluid of density ρ = 890 kg/m3 . When the beaker is placed on a scale, its weight is measured to be 1.00 N .(Figure 1)

A ball of density ρb = 5000 kg/m3 and volume V = 60.0 cm3 is then submerged in the fluid so that some of the fluid spills over the side of the beaker. The ball is held in place by a stiff rod of negligible volume and weight. Throughout the problem, assume the acceleration due to gravity is g = 9.81 m/s2 .

Part A

What is the weight Wb of the ball?
Express your answer numerically in newtons.

Part B

What is the reading W2 of the scale when the ball is held in this submerged position? Assume that none of the water that spills over stays on the scale.
Calculate your answer from the quantities given in the problem and express it numerically in newtons.

Part C

What is the force Fr applied to the ball by the rod? Take upward forces to be positive (e.g., if the force on the ball is downward, your answer should be negative).
Express your answer numerically in newtons.

Part D

What weight W3 does the scale now show?
Express your answer numerically in newtons.

 

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What is the magnitude of the electric force on charge A in the figure?

Part A 
What is the magnitude of the electric force on charge A in the figure?
F=______N

Part B
What is the direction of the electric force on charge A in the figure? Choose best answer.

  • (a)to the left
  • (b)to the right
  • (c)the force is zero

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