Answer:
276.135 J
Explanation:
Given that:
mass of Fe = 30.0 g
initial temperature = 24.5°C
final temperature = 45.0°C
specific heat of Fe = 0.449 J/g°C
We can determine the thermal energy added by using the formula;
Q = mcΔT
Q = 30.0g × 0.449 J/g°C × (45.0 - 24.5)°C
Q = 276.135 J
The speed of an object can be determined from the distance vs time graph.
You know that speed = distance/time
in the graph, distance/time = slope of the curve.
So SPEED IS GIVEN BY THE SLOPE of the curve in the graph.
● If the distance vs time curve is a straight line, parallel to time axis(x-axis), slope is 0. That means speed is 0. So the object is at rest.
● If the distance vs time curve is a straight line, with some non-zero slope; That means speed is nonzero and constant. So the object is in uniform motion.
● If the distance vs time curve is a curved, the slope is changing. That means speed is changing. So the object is in an accelerated motion.
Answer:
Number of turns per unit length will be 
Explanation:
We have given that strength of the magnetic field produced by the solenoid B = 7 T
Current in the solenoid i = 200 A
Let the number of turns per unit length is n
Magnetic field due to solenoid is given as
here
is permeability of free space n is number of turns per unit length and i is current
So 

An instrument used to observe or imagine very small object using an optical mangifier
mirco cell.
Telescope is a magnifer of distance object
Answer:
Two positively charged particles
Explanation:
I said two positively charged particles because if I say c or d what ever it is for you guy it can be wrong so just pick the one that says Two positively charged particles