a vacum tube can be used to
change alternating current into direct current
increase the strength of a signal
turn a current on or off
all of the above
 👍
 👎
 👁
 ℹ️
 🚩
1 answer
Answer this Question
Related Questions

physics
A 10 ohms resistor has a constant current. If 1200C of charge flow through it in 4 minutes what is the value of the current? A) 3.0 A B) 5.0 A C) 11 A D) 15 A E) 20 A ok I used the I=Q/t, 1200C/240s to get 5A which is an answer. You said I was right but
 asked by susan

Algebra
The current of a river moves at 3 miles per hour. It takes a boat 3 hours to travel 12 miles upstream, against the current, and return the same distance traveling downstream, with the current. What is the boats rate in still water?
 asked by Ann

physics
A current of 30 mA flows in a conducting wire on a zaxis towards positive direction and three cylindrical coaxial current sheets with diameters 5 cm, 3 cm and 2 cm carry current densities 60mA/m, 50mA/m and 40 mA respectively in the same direction.
 asked by aru

physics
if one resistor is removed from a parallel circuit, the total current will 1) decrease b) increase c) remain the same and the current flowing through each of the remaining branches ____________________.
 asked by Sejul

math
A boat's crew rowed 12 miles downstream, with the current, in 1.5 hours. The return trip upstream, against the current covered the same distance, but took 4 hours. Find the crew's rowing rate in still water and the rate of the current... The crew's rowing
 asked by sam

Statistics
Suppose the U.S. president wants an estimate of the proportion of the population who support his current policy toward revisions in the Social Security system. The president wants the estimate to be within 0.028 of the true proportion. Assume a 99 percent
 asked by Adam Dane

science past year
1.1. A resitance of 1.5ohm is connected in parallel with a resistance of 3 ohm. This combination is connected in series with a resistance of unknown resistance of value R. The circuit is then connected acress a 10 V supply. Calculate: 1.1.1. The value of
 asked by kamil

Math
In a circuit, the voltage, V, is given by the formula V = IZ, where I is the current and Z is the impedance. Both the current and impedance are represented by complex numbers. Find the voltage if current is 3 + 2i and impedance is 4  i.
 asked by Anonymous

science
Which circuit will have the greatest electric current? (1 point) circuit 1 circuit 4 circuit 2 circuit 3 Circuit A has a resistance of 7.5 ohms, and circuit B has a resistance of 5 ohms. Which statement about the circuits must be correct?(1 point) If the
 asked by h

Algebra II
A rowing team rowed 50 miles while going with the current in the same amount of time as it took to row 25 miles going against the current. The rate of the current was 2 miles per hour. Find the rate of the rowing team in still water.
 asked by Brice

Science
CHECK MY ANSWERS!!! Strength of Magnetic Forces 1) Which electromagnet will produce the strongest magnetic force? A) Electromagnet Y 2) A student connects a battery to a wire and wraps the wire around an iron nail to produce an electromagnet. Which action
 asked by ale

Physics ASAP!!
1. Three resistors are placed in series. They have the following resistances: R1 = 20 ohms, R2 = 20 ohms, R3 = 10 ohms. What current would be moved through this circuit by a 5V power supply? A. 1.0 A B. 0.10 A C. 25 A D. 250 A 2. Two resistors are placed
 asked by Ray

Algebra
Petra, who can paddle her canoe at a rate of 12 mph in calm water, is paddling her canoe on a river whose current is 6 mph. How long will it take her to travel 3 miles upstream against the current? Please help
 asked by Alissa

math
Electrical system are governed by Ohm's law, which states that V = IR, where V=voltate, I=current, and R=resistance. If the current in an electrical system is decreasing at a rate of 9 A/s while the voltage remains constant at 14 V, at what rate is the
 asked by christine

Math... with complex numbers
Complex numbers are often used when dealing with alternating current (AC) circuits. In the equation V = IZ, V is voltage, I is current, and Z is a value known as impedance. If V = 1+i and Z=2$, find I.
 asked by Anonymous

math
A boat traveled 45 miles downstream (w/ the current) in 3 hours and made the return trop (against the current) in 5 hours. What was the speed of the boat and what was the speed of the current?
 asked by mindy

Physics
The figure below represents a section of a circular conductor of nonuniform diameter carrying a current of 4.50 A. The radius of crosssection A1 is 0.300 cm. (a)What is the magnitude of the current density across A1? A: 1.59155e2 using J=I/((r^2)pi) (b)
 asked by Tony

physics
your boat departs from the bank of a river that has a swift current parallel to its banks. if you want to cross the river in the shortest amount of time, you should direct your boat a.) perpendicular to the current b.) upstream c.) downstream d.) so that
 asked by stu

Physics
Matt is attempting to sail a sailboat northeast across the river with a velocity of 13 m/s relative to the current of water. The water current is flowing from south to north at a velocity of 6 m/s. If the angle between the velocity of the sailboat and the
 asked by Joe

math
Bill swam 4 kilometers against the current in the same amount of time it took him to swim 12 kilometers with the current. The rate of the current was 2 kilometers per hour. How fast would Bill swim if there were no current?
 asked by mik
Still need help?
You can ask a new question or browse existing questions.