import json
with open('result.json', 'w') as fp:
    json.dump(sample, fp)

This is an easier way to do it.

In the second line of code the file result.json gets created and opened as the variable fp.

In the third line your dict sample gets written into the result.json!

There are a few issues here:

file = open('somefile.json', 'a',encoding="utf-8")

You're implicitly assuming that the file will be closed here. That is true on CPython, but not on all Python implementations. A better approach would be:

with open('somefile.json', 'a',encoding="utf-8") as file:
    file.write(json_obj)

Because that uses a context manager to explicitly close the file.

Second, you can avoid creating an extra string by writing directly to the file:

with open('somefile.json', 'a',encoding="utf-8") as file:
    json.dump(someDict, file)

Third, having multiple JSON objects in a file is not valid JSON. There are a few approaches you could take here. One is to wrap the JSON objects in a list:

[
{
    "a": 1,
    "b":2,
    "c": 3
},
{
    "a1": 1,
    "b1":2,
    "c1": 3
}
]

So, start the file with an open bracket, and write a comma after every JSON object, except the last one, then end the file with a close bracket.

Second approach would be to newline-separate your JSON objects, like this:

{"a": 1,"b":2,"c": 3}
{"a1": 1, "b1":2,"c1": 3}

Each line is a JSON object. You'd read this like so:

with open("filename", "rt") as file:
    for line in file:
        obj = json.loads(line)
        # do something with obj
        # ...

The advantage of this approach would be that you can now load each individual JSON object in memory, without having to load the entire file in at once. The disadvantage is that you're no longer writing valid JSON, so you can't use tools like jq on the output. (If you want the best of both worlds, you can use a package like ijson, but that's more complex.)