Answer:
an instrument for measuring an electromotive force by balancing it against the potential difference produced by passing a known current through a known variable resistance.
Answer:
The change in temperature, 
Explanation:
Given that,
The temperature in Spearfish, South Dakota, rose from
in just 2 minutes. We need to find the temperature change in Celsius degrees. Change in temperature is given by final temperature minus initial temperature such that,

The relation between degrees Celsius and degrees Fahrenheit is given by :

Here, F = 49 degrees

So, the change in temperature is 9.45 degree Celsius. Hence, this is the required solution.